Volvo RWD 120-130 Forum

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13 mpg... Maybe a clue? 120-130

Well, after gasing up today, 10 gallons with 135 miles. Man that's bad, about half of what it really should be... Leaning the carbs out results in very poor running, so I'm not sure what is happening anymore.

Well, I did have a new clue Saturday. After going out for a run to pickup a couple tools and some new auto fluids, I went at replacing both of my upper ball-joints.

When I went to remove my hubcaps, I noted that they were very warm. It was sunny and I figured it was just reflective heat, until I got deeper...

My wheels and my lugnuts were also very warm. So warm, in fact, I could not hold all five lugs in my hand. The wheel hubs were also very warm/hot - as were my front calipers. The outer part of the calipers are actually a tad discolored - kinda silvery.

One of my pads is a bit thin, but aside from the heat and the discoloration, I've had no other indication that my brakes are binding. I can spin the wheels freely with no issues.

I'm thinking maybe that my brake hoses are not releasing the pressure when I let off the pedal. I've read that they can collapse internally and function fine to stop, but not allow the pressure to release... I suspect that this might be the problem.

What other symptoms should I be looking for to confirm this diagnosis - you know aside from just replacing the expensive hoses for preventive maintenance?








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Another Leak?? 120-130

Well, I received my new brake hoses this afternoon, but there was not enough sunlight and warmth to deal with the hoses and calipers. I plan to rebuild at least one caliper and replace both front hoses this weekend.

But, I think I may have found another fuel leak. I still suspect that the brakes are not helping overall economy, but I noticed that there was some residual wetness on my in-line fuel filter when I was checking over my engine this evening.
The filter was all tight and clamped, but I think the seals may have been leaking a lot of fuel.

Since I have a glass-dome filter with the internal filter screen, I have completely removed the inline and put in some solid rubber tubing and some new hose clamps. I will now rely on the screen and the pump design to catch any more crud from my newer fuel tank.

I hope that I will see some improvement in fuel economy. If not, I still have a serious problem someplace that may go above the binding brake pistons...








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What kind of fuel filter are you using? Just use one of those little plastic ones and put it in the engine bay somewhere... (nmi) 120-130








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I Had one 120-130

Oh, I had one of those. It clogged up entirely in around 5 hours when the car was being resurrected, and I've not messed with another one since. I have to flush my filter daily due to a cruddy tank that defied a thorough cleaning when removed. The new tank has some slime that has gradually dissolved out of the tank, but I seem to be on the tail end. I had to clean my filter maybe once a tank/week.

Honestly, based on the fuel consumption this evening, I'm not sure removing the in-line and relying on the pump filter has made any difference...

I'll have to see at my next fill-up.








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I Had one 120-130

When I first got my 142, I was replacing them daily, then weekly, then monthly... Then longer than that. I think my gas tank was leaking too, and it was definitely rusty. 4.5 years went by and I never took it out to have it repaired/sealed. Now the car's in someone else's hands. I never got above 20mpg in it either, actually, I think I got 22 once but that was not normal.

The filters are so cheap and easy to swap I didn't mind having a bunch in the trunk or an extra in the glovebox.

Sounds like you've taken care of most of your fuel filter plugging issues, definitely get one back on there though! No reason to run without a $2 clear filter on there. You can look at it to see if it leaks, mine normally wouldn't even without any clamps on. I have seen fuel pumps themselves leaking externally, but you'd've already seen that.

I don't know what to tell you man! This shouldn't be happening!
--
Kyle - 244! - Kawasaki Ninja 250R - Oregon Volvo Tuners?








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Kids, don't try this at home. 120-130

Repairman,

At 13MPG, that much fuel going into the engine would smoke black and it would have no power at all.

If bearing or brake drag is the culprit, you'd have a hell of a time accelerating from a stop. You should be experiencing heat fade. The car would be slow, slow, slow.

I trust that none of that has happened or you would have let us know about it.

I don't recall seeing a post where you specifically verified the accuracy of the odometer by either GPS or a known distance. But I assume you have covered that base.

That leaves a leak.

My guess: the 40+ year old fuel line that was left to stand for an unknown period of time with no fuel in it has pore sized holes that seep fuel as suction is increased by the pump as RPM goes up. Air comes in, fuel goes out. Because it is along the bottom the fuel evaporates quickly in the airstream; by the time you get the car on jackstands, all evidence of a leak has evaporated. Because the pump pulls less suction at idle, there is enough surface tension to block the flow of liquid through the tiny holes, stop the leak, and therefore no telltale puddle under the car when parked.

Yes, I know. That is pretty far-fetched. Pore sized holes that stop leaking when fuel demand goes down is really not my favorite explanation. But I actually experienced a similar problem as a teenager. In that case it was the hose that attached to feed side of the pump.

Put a one gallon plastic gas can behind the grill and in front of the header panel. Run a fuel supply hose to the pump from that one gallon can. Be sure you tilt the can and position the hose to get as much fuel out of the can as possible. Duct tape and ty-wraps are your buddies.

Drive the car until that one gallon can is empty. (Carry a fire extinguisher; you never know what will happen on the streets.) I will wager a nickel that fuel consumption is lower than 13MPG. Depending upon conditions, it will most likely be something lower than 22MPG. Even if I'm wrong you will know whether the excess consumption is before or after the fuel pump.
--
Mr. Shannon DeWolfe -- (I've taken to using Mr. because my name tends to mislead folks on the WWW. I am a 51 year old fat man ;-) -- KD5QBL








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I like your logic, but wouldn't there still be the smell? 120-130

Even if the leak is inperceptable visually (puddle, wetness), wouldn't an overwhelming smell of raw gas be present?

Repairman, any smells beyond what's normal? Normal being a relative term given all the fuel system related work you've been through recently. But then, if the fumes are really bad, you might not be in a right state to answer!

-Will
--
850 / Mini








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Smells as leaks 120-130

well, first off, I have verified my odomter to be very close to correct. My trip failed suddenly a couple weeks after I replaced the plastic gear but the regular odometer continues to flip over at the proper intervals.

Weird failure huh? It means that either the brass part of the gear is broken or that the trip innards have failed. Either way, with the regular odometer running, I do not want the hassle of pulling the whole panel again just for that. Long and short is that the main odometer reads consistently and close enough to actual mile posts for me to rely on it.

I do have odd smells, but usually not fuel. I do get fuel smell when I am running under choke, but that's about it. I am definitely not burning that much fuel in the engine, and I very rarely see smoke out the tail pipe. I think loss is reasonable, but the lack of a strong smell has consistently kept me away from that as my main issue.

I find that despite verifying the condition of the remaining original steering rod and lower ball joints, and having replaced the rest of the steering linkages, the car pulls a bit to one side. Aside from a possible alignment problem, I attribute this to some binding of the brakes.

My single thin pad and hot wheel, hub and caliper also tell me that I have a real problem there.

But I do agree that I have no particular problem accelerating and do not have a sense that I am being slowed down by brake binding at a level high enough to ruin my mileage so seriously. 13mpg is about half of what I expect to be getting, and it was actually getting *much* less when fuel was leaking out the carb float chambers (<10mpg).

Today, when I arrived home, I found that I had driven over 140 miles on this tank and that my fuel gauge was reading at the 1/4 ( or 2/5th depending on how you read that gauge). Assuming that means that I really have 2 or 3 gallons left, that puts my mileage at around 18-20 mpg - a huge improvement and maybe even better considering that this was a mid-week repair.

I removed the suspected leaky fuel filter on Wednesday evening after my gauge was at half a tank of fuel (and reportedly at less than half of my actual fuel), so my fuel consumption may have actually improved quite a bit that that off-the-cuff calculation.

I'll need to finish this tank and fuel up again at the same station, pump, and car position to get a better sense of the change, but I *MAY* have finally traced the biggest loss of my precious fuel.

I have been thinking that replacing the fuel line so that I have all-new hardline from the tank up to the filter pump, and maybe from there to the carbs might be a good thing.

That would have fewer points of potential leakage, but I would have a bit less protection from stray crud in the fuel tank. Maybe I should put rubber hose with a paper filter after the filter/pump to catch the really fine stuff before it gets to my carbs...










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Another Leak?? 120-130

Maybe your fuel pump has a failed diaphram and is leaking oil into the crankcase?

Cameron
Rose City








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Another Leak?? 120-130

I'm not really sure if I've been losing that much fuel from a seal on the filter. I seem to be near the end of the tank grunge, so I just omitted the second filter and am relying on just the pump's screen. One less variable... I'm not sure it has made any difference at all, but I'll know more when I fill up next.

That's potentially a problem, but this particular AC pump was completely rebuilt with a new kit late last year. The kit included a new diaphram, valves, and rubber sealing ring. I've also been tracking this problem across multiple pumps. 1 pierberg, 2 AC dome pumps, and 1 "new" (read plastic core) replacement.








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Another Leak?? 120-130

Uh, I think you mean the fuel pump is leaking fuel into the crankcase.

Regarding fuel filters, I don't think I would rely exclusively on the brass screen in the fuel pump; the mesh simply isn't fine enough.

If the filter keeps clogging; it would be worth taking a peek inside the gas tank to look for rust. If there is any amount of rust your filter will continue to clog for all eternity (until you get rid of the rust).

Even the paper fuel filters don't catch everything. I found a fair amount of sediment in the bottoms of my Mikunis when I replaced the float valves. The carbs had less than a thousand miles on them. I had a rusty tank...

It might be worth taking a peek into the float chambers of the SU's to see if the bottoms have filled up with crud.

Bill








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Another Leak?? 120-130

Thanks, I spend a lot of time checking inside the su floats and jets looking for causes of fuel loss.

I'm relying on the diminished rate of the accumulation of sediments in my filter as well as both gravity in the pump reservoir and hydrodynamics to drop the crud into the filter dome before they get sucked up into the filter screen.

Really, the removal of the filter is a short-term check to see if my fuel economy really improves. I'll probably put something better in when I can rule out my renewable filter as a source of significant fuel loss.








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Another Leak?? 120-130

Oops - yep: I meant gas might be leaking into the crankcase. Not oil. Heh.

Thanks,

Cameron
Rose City








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Another Leak?? 120-130

yeah, i understood what you meant.








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13 mpg... Maybe a clue? 120-130

My bet is sticky caliper puck/s.
I have had both conditions.
When the flex hose clogged the wheel skidded.
When the caliper bound the brake dragged.
--
71-145-S ; 72-145-E ; 72-1800-ES








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13 mpg... Maybe a clue? 120-130

i WOULD replace the hoses if they haven't been done in the last 2 yrs.&then use a pressure bleeder like the one from FCP .I used it on my 245&it flushed whatever was sticking up my front cyl.Cheaper than replacing the caliper&more ecologically responsible.








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Pistons and Hoses 120-130

Well, this car sat for 22 years unused. I began driving it as soon as I flushed everything out back in July. Aside from bleeding, I never messed with the brakes because the car stopped fine and the pads were quite thick when I woke the car up.

I plan to do both the hoses and replace the sticking pistons. The hoses are quite old but look solid. The tires on this car had dry-rotten but were still holding air. I suspect that the hose rubber should be replaced even if the rubber looks fine. I'd like to go with the stainless hoses that IPD sells, but given the investment, I think I should wait until I have my dual-circuit calipers ready to go and buy a set of those...

As far as sticky pistons. From my most recent inspection, My driver's side caliper must be sticking on one side. The outer pad is heavily worn, while the inner pad has lots of life.

On the plus side, I have two fully-disassembled caliper cores, and one OEM volvo rebuild kit. I also have the single-circuit calipers left over from from my 122S Wagon dual-circuit upgrade. Those showed uneven wear, which probably means there is a stuck piston there too...

I also have a pair of dual-circuit 4-piston units needing a rebuild, but at $60.00 a kit, I'll need to resist that upgrade for a little while.

As soon as my new parts arrive, I'm going to get this taken care of. I hope that I see an improvement in my mileage...








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13 mpg... Maybe a clue? 120-130

Just out of curiosity, have you been using the same filling station each time you do your mileage check? If so, are you certain their pumps are accurate, or that they're not trying to scam customers by tampering with the pumps. I know the pumps are supposed to be checked by some government agency, but still...

You're not using fuel with ethanol in it, are you?

Sticking handbrake cable?

Any chance the wheel bearings need grease?; dry bearings will generate a lot of heat.

Is there an invisible 500 lb woman who likes to sleep on your backseat?

Bill








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Ethanol in the Fuel 120-130

I'm not sure. None of it is marked as E85, but you never know... I have noticed that my fuel tank is being scoured by successive refills as my fuel filter continues to get clogged.

I fill up a one of three or four stations. Usually the Quicktrip near work or the Citgo near home. I occasionally fill up at BP about halfway home, but only when I fear I might run out. I've been tracking my fuel consumption mainly by fill-ups at the Citgo. If they are screwing me over, I'm counting on it being a consistent screw-job.

The front wheel bearings were re-greased back when I was tracking a persistent thunk noise. That turned out to be a very bad steering rod and upper ball joint...








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Ethanol in the Fuel 120-130

A lot of the time, here in StL, you get E10, 90% gasoline, 10% ethanol. That will give you slightly worse MPG, nothing major though. Actually, it gets slightly worse MPG in a fuel injected car because the O2 sensor will trigger it to inject a little more gas to get back to stochiometric, I think a carbed car would just run a little lean. But still, it's a very subtle difference, intentionally so, because if an injection computer has to fudge the mixture too far to get a good O2 reading it will light the CEL.

E85 requires about 30 - 35% more fuel compared to straight gas, so the MPG goes down by roughly that percentage too. I'd be running it in the turbo wagon (it's something like 105 octane, and with my programmable Megasquirt controller it's be simple to bump the fuel levels up) but nobody is selling it, and I think last time they were selling it they were pricing it the same as gas, which makes no sense because you use 30 - 305% more of it to go the same distance.
--
'63 PV544 rat rod, '93 Classic #1141 245 +t








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Dupe, please ignore 120-130








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13 mpg... Maybe a clue? 120-130

On the 140/164 the problem you cite (collapsed hoses acting like check valves)
is common because of the small size of the hose and the tight crimp of the
ferrule near the hose barb. I have never heard of this being a problem on a
122. But it does sound like you have a dragging brake.
Do you have any kind of power brake unit installed? If you CAN turn the wheel
freely it doesn't sound like the brake is dragging but there may be other things
involved. Loose wheel bearings will allow the disk to lean against the brake
pad, for example.
--
George Downs, Bartlesville, Heart of the USA!








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13 mpg... Maybe a clue? 120-130

Dang, I just put in an order for new hoses... like minutes ago... I went with the stock type hoses as opposed to the expensive stainless braided hoses so the price was not too bad.

Ah well, after sitting for 22 years, it can't hurt to replace them.

My brake system was upgraded to a 140 booster and master cylinder a few months back. It looks like a 123GT setup and stops the car *very* well.

I can spin the front wheels and hubs freely when it have the front jacked up.

I checked over the hubs and grease a few months ago. I did not see or feel any play in the wheels when spun. The front bearings seemed okay - as best as I can tell with my hand and eyes. No weird rumbly noises when I drive.

But, I can't get around those wheels being so hot. I was not doing a lot of high speed stopping, so I cannot account for the heat or the caliper discoloration. I've never felt them like that.

I this Rhys might be onto something with the pistons. The car came with a complete OEM piston rebuild kit. Maybe the original owner suspected...












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13 mpg... Maybe a clue? 120-130

It is far more common to find the caliper pistons siezed than to find brake hoses acting as check valves. I'd pull the pads and jack the pistons out a bit with the pedal and then return them the same amount with a small prybar. That will tell you if the pistons are sticking. Maybe even lift up the edge of the boot. If it's rust brown in there, it's the pistons.








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13 mpg... Maybe a clue? 120-130

I think many owners who've had their car parked up for a few months will have had their front brakes stick on, even if they've appeared to be OK after a run around the block. Leaving the possibility of a collapsed pipe out of the equation, sticking pistons is common. Trouble is you have 3 of them and the brake will work after a fashion with only one of the smaller ones working. They might all work with different pressures, depending on how badly they are sticking. If one pad is wearing more than the other it's a sign of sticking. The pad on the side with 2 pistons may be worn at an angle which also gives a clue. If you can roll the car around by hand, either when it's cold or after driving, I'd suspect the pipes rather than the calipers. You probably don't notice that you're using a bit more pedal to get the same performance but there might be a hill somewhere that you remember that you could always pull top gear and now you have to change down. If you're changing the pipes you might as well get the calipers on the bench too. A small bet that there is at least 1 piston stuck? Maybe even 1 each side if you can brake in a straight line with your hands off the wheel. I think having bad/sticky/stuck pistons could well be the reason that some owners think that the Amazon brakes are poor or barely adequate. With the right pads they are good enough to race with, so they can't be that bad.








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13 mpg... Maybe a clue? 120-130

I've never seen a stuck caliper, I've never needed to rebuild one either.

I guess that's the salt factor for you people with snow.








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13 mpg... Maybe a clue? 120-130

Yep, most definitely a regional sort of thing. I've had plenty of stuck calipers over the years, and never once saw a brake line that didn't flow properly.

Old cars are rare where I live, and the only ones that survive are the ones that are not driven in the winter when they salt the roads.
--
'63 PV544 rat rod, '93 Classic #1141 245 +t








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13 mpg... Maybe a clue? 120-130

It may be regional, but one look at the goofy dust boot arrangement on the Girling three piston calipers and it's obvious that they don't seal well.
I have never dismantled a three piston caliper and been able to re-use all of the pistons due to extensive rust pitting. Just dismantling them can be a real bear, as there is little to grab and they should be jacked out hydraulically. I have then had to either exchange them with reman units, or dismantle a few to get enough pistons to build one set.
Now I purchase stainless steel pistons and that solves the problem.








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13 mpg... Maybe a clue? 120-130

When I put my junkyard 3-piston calipers on the PV, I pried the boots back a little and packed the insides with a little of that brake grease. Not sure if it will do any good, but it might.
--
'63 PV544 rat rod, '93 Classic #1141 245 +t








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13 mpg... Maybe a clue? 120-130

I am sure it will help John - anything to keep water out of the piston to bore area.








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13 mpg... Maybe a clue? 120-130

The Brits love to build brakes that only work sometimes... I used to drive BMC stuff, and the pistons were always seizing in their bores. Eventually, brakes became as regular a maintenance item as oil changes: take the wheels/drums off, remove pistons, clean out the bore, coat bore and pistons with anti-seize, new cups, reassemble. After a few times, the whole car could be done in just over 1/2 an hour, and the brakes were completely reliable.

Whether this would work on your units I cannot say for lack of first-hand experience, but it might be worth a try...








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13 mpg... Maybe a clue? 120-130

My experience has been a bit different, with collapsed hoses outnumbering stuck pistons (although the former seems to lead to the latter pretty quickly).

It's easy to tell: if the pistons are hard to retract, open the bleeders. If they move freely, it's the hoses. If it doesn't make it easier, it's the pistons.








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13 mpg... Maybe a clue? 120-130

Just thought I'd throw this into the mix -- there is one more thing that can cause the brakes to drag; insufficient freeplay on the pedal. I'd check that the rod for the master is retracting fully. As you say, it can't hurt to replace old hoses and it is probably a good idea to throw new seals at the calipers too. Shotgun approach is OK; it's the brakes.

sd








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13 mpg... Maybe a clue? 120-130

I'd pay very close attention to this suggestion. I had the same problem with my disc conversion on my P210. I used the original (non-boosted) master and single circuit Girlings from a 122, rebuilt with SS pistons. No matter what I did, I could not keep the brakes from freezing up unpredictably while driving. Hell, once (I'm not making this up) the car was just idling in the driveway and I happened to be behind the car when I saw the brake light come on. I replaced the master with a fully rebuilt unit and changed the system fluid over to silicon. Nothing made a difference until...

Someone here on BB suggested I back off on the pedal adjustment (more freeplay). Yup, that's what did it!. New car now. If you look at a schematic of the master cylinder it's very easy to see why this might happen. I've also heard that the equalizin hole may become blocked off (in which case even freeplay won't help you).

Thanks BB!!

longhorizon








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Something To That 120-130

I've not had any indication that my pedal is cause trouble. The brakes are not engaged when the car is on jacks, and they do not grab until I have the pedal partway down...

However, I did convert my MC to a 140/123GT type and that required me to adjust the actuating rod pretty far out so that the system would boost properly. It's possible that I have it too far out. I'll check that after I get into the hoses and pistons. I know for sure that one of my pistons is dragging...








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Something To That 120-130

The problem usually evidences itself sfter the car's been driven. The heat generated by braking will expand the fluid & cause pressure to remain in the system. Drive it hard ,then park it & jack up the wheel to see if it's free. If you can't turn the wheel easily then crack the bleeder. If fluid is released under pressure then it's a hydraulic problem;either hose or master adjustment too tight. If more than 1 wheel is tight it's probably the master adjustment. If just the one then the hose. Stuck calipers are very common back in the midwest[where I'm from]but iwould suspect the master adj. since you don't mention any pull or eratic braking.Found this a lot with Brit cars in the 60's when owner's wanted a "higher" prdal. Interestingly I've found that after a rebuild of calipers you would often have a "softer" pedal than with a sticking caliper,even after extensive bleeding. Better modulation though. I also experienced a collapsed hose in a 67 Saab 96 that I owned. Good hunting.


Mike M.
Greentoad II Now with more "ZOOM ZOOM" due to head porting AMAZING-IT WORKED!









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13 mpg... Maybe a clue? 120-130

I'm wondering if such a problem could be tied in to the power brake conversion (brake drag).
Try pushing the car with the engine running, and have someone stomp on the brakes immediately before each attempt at pushing and see if the car gets harder to push.

Bill







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