Hi,

This is a car I acquired late last summer in seemingly excellent shape, but I have no service records.

It recently developed a growly once-per-wheel revolution noise that I first thought might be a sticking caliper. It turned out to be a front wheel bearing but before finding it I checked out the calipers. The rear driver's side was not releasing as I thought it should, so I pulled it and began rebuilding it. When I split the caliper there was a snotty brown lump stuck around the O ring.

I'd never seen anything like that and wondered if it had the original brake fluid. I also figured there'd be more trouble ahead.

I buttoned it up and bled the brake and it retracted a lot better, but the next morning the brake failure light stayed on after start up. I shut it down and it stayed off after restart. It did this again in the afternoon but came back on a few miles later and it's been on ever since.

I know it could be air in the system, but I've bled the whole thing twice now, running a gallon of fluid through with no solution, so I'm wondering now if I haven't pulled some gunk into the switch at the junction block. The pedal is high and hard and this is a very busy time of year for me, so before pulling it I'll hope that the clean fuid might dislodge it, but I dbout it will.

I have an old spider from my parts barrel that I took apart to see what I could see and it looks like the switch piston only has to move less than a millimeter to contact the end cap, so a litle rust there might be making a connection. I may loosen or take off the caps before going further.

Any advice would be appreciated. One other piece of information is that when I was bleeding the system, the pedal would not go down as far on the side of the rebuilt caliper as it would on the other side. The rebuilt caliper is on the circuit with the 2 upper front. The pedal on all 3 of those bleeders would stop a little past halfway to the floor. Is that normal and if not, why ?

Thanks, Peter

And I'll bet the brake fluid in in your 1988 Volvo 240 brake system was quite black and rotten for sometime before the problem developed. It's really best to replace all fluids once you purchase a used vehicle, unless you have records and visual inspection that shows fluid to be topped up and clean. Brake, coolant, transmission, rear differential, we already know engine oil, and other fluids and so on.

Change break fluid every two years. Or, just as it loses the golden, light tan color in the reservoir. Same for coolant, differential fluid, and so forth.

If one wheel bearing show distress or is failing, inspect the corresponding hub on the other side. Use new inner hub seals and a good NLGI-2 grease. How are them rear wheel bearings? They use grease, also.

The brake light, if the brake systems sensor is fine, shows an imbalance between the two brake circuits. You may have some air in one brake circuit, causing the break sensor to react to the imbalance with the corresponding brake systems failure indicator lighted on your dash head.

Using the break pedal to pump new fluid through the dual-circuit brake systems on your 1988 Volvo 240 may not be the best way to do it.

Even with one-way break bleeder nipple at each caliper bleed nozzle, air can draw back into the caliper along the bleeder nipple and brake caliper thread interface. Best to do the pedal brake bleed with two folks. One at the brake, one at the brake caliper.

At the break caliper, close the bleeder nipple as you depress the pedal.

The only other option you have is a gravity bleed. Open the bleeder nipple to drain the old black brake fluid and keep the brake fluid reservoir clean. Gravity bleed is quite gentle and may not force out as much particulates, certainly in the two brake check valves that serve the rear brake calipers.

So, perhaps try the Motiv or like power bleeder. It works.

Someone else may chime in with other suggestions.

Questions?

Hope that helps.

Buttermilk.
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The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity

Thanks Mr. Buttercup,

Good advice, as always, and I agree. I've only put 1500 miles on the car and I'm in the process of doing all you suggest. My old boilermakers ears had convinced me that the growl was in the rear, so I pulled both axels. You'll be glad to know that I renewed the seals and bearings while I was there. They weren't terrible, some noticeable wear and starved for grease as the inner seals had not failed. These new ones will outlive me, I'm fairly sure

The M47 oil was surprisingly clean and overfilled so that was good, and I'll do the rest of the fluids as time permits.

I have an opened spider with brake failure switch in front of me and I'm trying to understand it's operation. I know on some dual circuit systems the switch moves to one side at a brake failure an stays there until reset. The Volvo switch seems to self center under spring pressure, so it looks to me that the light will only activate when there is pressure on the pedal. I've never had a real brake failure so I don't know, but if I'm correct then it follows that if the light is on continually without pedal pressure, as mine is, then the switch is out of whack.

It looks to me that little or no fluid is able to get by the switch from one side of the system to the other, so that on a poorly maintained system the switch could easily be seized in the neutral position and the operator would not know. I'm assuming also that one could test it by opening a bleeder to simulate a brake failure, and applying pedal pressure with the car running.

There have been numerous warnings on this forum about the danger of taking the pedal to the floor when bleeding. To my mind, an open bleeder is the same as a brake line failure and I don't understand how there is safety in the system if the pedal is able to go to the floor. In my case the pedal stops halfway when bleeding one side of the system and goes to the nearly to the floor on the other. Does this indicate a failing master cylinder ?

Lastly, I remember coming across an old post about replacing the brake failure switch. I made a note in my Bentley, Volvo part # 272702-2. I don't know if it's still available, but I can't figure out how to remove the old one. Is it just driven out ? I'd like to look at it but I don't want to destroy the spare I have.

Thanks, Peter

Hi Peter,

Thank you.

Good job on them rear wheel bearings! How are them U-joints on the drive shaft column in the engine bay? Any play?

Indeed, the pressure differential warning valve is an assembly body to which numerous brake lines secure. You'd replace the assembly complete, if it is indeed failed. Or use a kit to to replace the innards using Volvo PN 272702 (an old number)

If the brake fluid was many years old, it could cause failure by particular deposit or rust particles as very old brake fluid has ever more water in it. Brake fluid sucks up moisture.

What I see for Volvo PN 272702 is a rebuild kit, and not the replaced valve body.

Courtesy, FCP Groton:


Link to page for kit:
https://www.fcpeuro.com/products/volvo-brake-line-junction-switch-240-740-760-244-245-242-260

My concern on a 27 year old 1988 Volvo 240 is that the bronze brake lines have expanded from years of fluid pressure as the driver applied brakes, and you may not be able to remove them from the valve body with destroying them. I can be wrong. You can try so carefully, yet.

You can also merely replace brake line junction assembly using Volvo PN 1273052. I replaced this item in the late 1980s on my 1975 244 DL and again on my 1979 242 GT, as the prior owners may have never replaced the brake fluid.

Courtesy, iPd:


Link to page for kit:
http://www.ipdusa.com/products/5135/103062-brake-junction-block

iPd sells an after market brand. Compare the casting and machining. Quite a difference.

If you get Volvo PN 272702 to rebuild the brake systems differential pressure switch, please be clean about it.

If you try to loosen the brake line connection to the valve body, and the bronze brake lines twist as you turn the brake line retaining nut, I'm unsure how you can disassemble it without having to replace some of all brake lines.

Sometime releasing the failed valve body, if indeed so, from the frame, and carefully rotating it to straighten some sharp turn on the brake line may release the brake line retaining nut with the expanded section of brake line above it.

If you can deal with the risk, you can install a new Volvo PN 1273052. Just be sure you have spare brake lines or have a vendor that can fabricate them for you nearby. It can take sometime to get replaced copper brake lines as the dealerships don't stock them, yet online, of course, may be better than the brick and mortar.

Hope that helps.

Questions?

Thanks,

Bruce.
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The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity

Hi Bruce,

Thanks. I also replaced one long ago and can do it again, but I woke up this morning with a much simpler and permanent solution. I pulled off the connector to the switch, melted a little heat shrink onto it and stuck it back into the booty.

The light now comes on with the key and goes off at start-up, just like every other man's Volvo. It will pass inspection as I don't believe there's a vehicle inspector in this world or the next who'll run the car with a bleeder open to test it.

It also ends the strange looks and rolled eyes of my passengers, mostly female, who don't seem to understand that a glaring, red BRAKE FAILURE WARNING is not a big deal. I'm tired of being mistaken for a homicidal maniac.

I'm a ex school bus driver and extremely cautious, but I can't see how this warning system provides any level of safety at all. If I'm on the highway and a bouncing rock severs a brake line, I would be none the wiser. 20 miles later when I'm swerving and braking to avoid a moose, the light would come on. It would be useless, nothing more than a distraction.

I think if Volvo was serious about providing warning they would have put in a sensor to monitor the brake fluid level in the master cylinder reservoirs. That would give you half a chance to pull over and investigate before you needed your brakes. As it is, it's no better than replacing your gas gauge with a warning light that reads, " By the way, you're out of gas" that comes on just as you're sputtering to a halt.

If you or anyone else knows of any good reasons why I need this thing I'll fix it, but until then I'm filing it away with the comp board and the service reminder.

Regards, Peter

Hiya Peter,

Thank you and Happy Munday (all day long)!

Whaaaaaaat? You have the better gender, and that's not us Volvo 240-powered men, riding around in your Volvo 240 with you? Wot's your secret? Unless these folks are family!

I'd not had me a date in a long time. The last few dates in St. Louis up to about a decade ago were nothing going no where. A decade next month.

I do have the brake fluid reservoir level sensor in my Volvo 240 as well as the differential pressure switch. You can retrofit your 240 using a brake fluid reservoir with the fluid-level sensor on the ATE brand brake master cylinder.

The sensor is wired to the same light as the brake warning failure light. Some may do it separately.

Some may also retrofit the coolant level sensor to their 240 and wire it up to a dash light position, if one is open.

Welp, that sensor indicates an imbalance in the system in that one of the two brake circuits is without brake pressure. So, you have 70% braking or so. So, it does serve a safety purpose.

So, I'd be a little worried you have disabled this feature, if so.

Else, well, I dunno.

Taking a packing break. Going to WI, MO, MN, or I dunno.

Switzerland. Just and verdant Switzerland.

Thanks.

cheers,

Monday's MacDuffed.
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The Volvo 164: The Mightiest of All Volvo Automobiles in Perpetuity