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I have the Haynes manual and this looks fairly straightforward but any hints or tips would be appreciated as I'm a brakes virgin!
What's the best way of compressing the caliper pistons?
What holds the rear rotors on and should I do the pads first before taking the caliper off to do the rotor or does it matter??
Thanks
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As mentioned B-4 I would read the FAQ and I use an old fashioned "C"-clamp to push the calipers back in. Shouldn't take you more than a 1/2 hour. Calipers are held on with two bolts.
I personally leave the old pads on to protect the caliper/piston when using the wrench or C-clamp to push them back.
Good luck
--
EJO now a 1993 944T 209K; ex '65 123S; ex '75 245; and ex '81 242GT; also 2001 Kia Sportage, Chrysler 2002 T&C and 2006 MINI Cooper
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Thank you for all the replies. I finally got to it this morning and my brick is sporting fresh rear Brembo rotors & MetalMaster pads, even better than that, I have a fresh VA inspection sticker...
I took your advice about leaving the old pads in the caliper and pushing the pistons back with a C clamp, worked great. I did read the FAQ before posting but it doesn't go into enough detail re compressing pistons IMHO.
Thanks again.
Matthew
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See the FAQ instructions on doing this job. First remove the old pads, then the caliper, then change the rotor which is held on by the locating pin. Make sure your emergency brake handle is not engaged. Best way to compress the pistons is with adjustable pliers: open the bleed screw, place a metal shim in front of the piston so you don't cut the boot, insert one plier jaw over the piston edge and the other over the tang at the back of the caliper, and compress. Tough to describe, easy to execute. The job is quite simple.
--
See the 700/900 FAQ at the "select shortcut' button, upper right of your screen.
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You also want to open the bleeder screw and clamp the brake hose with a round jaw or cushioned locking pliers of some kind before you move the piston. a special tool is available for this if your just looking for a reason to buy another tool.
This is to prevent any contamination from being pushed back into the brake line or into the ABS junction block.
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...in fact some manufacturers warn agaist doing so.
With an open bleeder, there is (IMO) no chance of any possible contaminants going several feet upstream to the ABS modulator.
I'm not alone in this opinion:
BIG 3 BRAKE SYMPOSIUM 2002
(excerpted clamping comments)
• GENERAL MOTORS PRESENTATION, Russ Dobson - GM Service Operations, Warren Tech Center
>CLAMPING BRAKE HOSES? GM says NEVER! Risk of damaging hose too great.
• FORD PRESENTATION, Garrett Van Camp & Chris Oakwood
>CLAMPING BRAKE HOSES? Ford does not recommend clamping hoses. . . This may damage the hose and increase the risk of hose failure.
I don't mean to offend anyone by opposing what I believe to be a myth. But it upsets me to think how many "newbies" come across it here, repeated endlessly as "Gospel". My concerns about crushing the brake line may be unfounded, but to my knowledge so is this brake line clamping idea. To me it's not worth risking needless hose damage.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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This is a cut & paste from the Brickboard FAQ just so you know that I didnt get it from, or am I myself a "newbie".
Brake Job Tips: Hose Clamp; ABS Sensors.
Forcing Dirty Fluid Back into the ABS:
[From Motor Service Magazine] We believe the biggest brake bungle techs are making today is forcing caliper pistons back without clamping the hose and opening the bleeder. Since the line comes in near the bottom of the cylinder where the sediment is, this forces debris up into the ABS unit, and that will likely result in a comeback for a glowing anti-lock warning light. Just opening the bleeder as you may have done in the past isn't good enough anymore. You've got to choke off that hose. [Editor's note: you can buy inexpensive plastic pliers with rounded jaws designed to clamp rubber brake hoses without damage. Check your auto parts store.]
If this information/advice is not valid then it should probably be removed. I fully realize that not every post I read on this board is accurate or recommended information, but when it checks out with what the FAQ says I usually think it is more credible. Not that I disagree with your point but I'd like to think that the first and maybe best place to go for accurate information is actually accurate.
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Brake Job Tips: Hose Clamp; ABS Sensors.
Forcing Dirty Fluid Back into the ABS:
[From Motor Service Magazine] We believe the biggest brake bungle techs are making today is forcing caliper pistons back without clamping the hose and opening the bleeder. Since the line comes in near the bottom of the cylinder where the sediment is, this forces debris up into the ABS unit, and that will likely result in a comeback for a glowing anti-lock warning light. Just opening the bleeder as you may have done in the past isn't good enough anymore. You've got to choke off that hose. [Editor's note: you can buy inexpensive plastic pliers with rounded jaws designed to clamp rubber brake hoses without damage. Check your auto parts store.]
• "Since the line comes in near the bottom of the cylinder..." "Bottom"? Not on any Volvo calipers I know of.
• "...this forces debris up into the ABS unit,". Depending on the caliper location, the path to ABS unit is something like 3' to 15' of brake line full of fluid—as is the ABS unit OR junction block. With the bleeder open, what is the path of least resistance going to be?
I don't know why this is still in the FAQ. I've rejected this in a earlier version before, as being from a less than credible source—a magazine writer, not a Volvo Tech.
Opening the bleeder first is key. Below is is my critique of the previous FAQ version (apparently accepted as gospel with no vetting by anyone I know of). I still believe my comments are valid and support my No-Pinching advice:
=======>Long Reply, referring to earlier FAQ version of this tip
Yes, I thought the clamping idea probably came from the FAQ, but I don't consider a magazine tip to be a credible source—especially one with so many vague qualifying terms and a questionable understanding of the "path of least resistance" as applied to brake fluid. Here are my views on it:
"[Tip from Motor Magazine] Add the step of line-clamping the brake hose to the caliper when you retract caliper pistons. If you don't, you may be forcing brake fluid from the caliper bore (where rust and other debris may have collected) and sending this dirty fluid upstream. It's long been standard practice to open the caliper bleeder screws to give brake fluid a place to go while retracting pistons. However, sometimes the bleeders are partially blocked. In these cases, they may not let out all of the fluid that you meant to let escape. Instead, the fluid may take "the path of least resistance" - upstream. Nowadays, that's likely to send it to sensitive ABS components."
• This doesn't make any sense. Even a "partially blocked bleeder", would offer "the path of least resistance", when compared to the totally closed "upstream" path to the ABS modulator. Or does the writer suppose there is empty air space "upstream"? IMO, this alone discredits the whole "tip", as presented.
"If the vehicle you're servicing has a blocked bleeder, you may get around the problem by cracking open the fitting where the brakeline attaches to the caliper before retracting the piston."
• With a "blocked bleeder", I wouldn't be "retracting the piston" at that point. I'd either be fixing the bleeder or repairing the caliper. Advice like this makes me question the writer's experience and credibility—and thus again the whole "tip".
"For added assurance, you may also want to line-clamp the hose feeding the caliper with genuine clamps designed for this purpose."
• I've never seen any "genuine" brake hose clamps. Probably because I've never looked for any. I doubt many DIY'ers have either. And I think it's wrong to send them looking for something that may not be worth using, based only on a questionable magazine tip.
Line clamps are used on pliable fuel, vacuum, or coolant hoses. I just don't agree with needlessly subjecting brake hoses (some with semi-rigid inner liner) to any crushing forces.
I also question "references" to clamping a brake hose to prevent fluid loss when changing the caliper, beacause it's just not necessary. Fluid loss from an open line can be easily prevented by blocking the brake pedal depressed (while bleeding off the resulting pressure). The MC piston seals will block the reservoir ports and no fluid will flow, except for a drop or two when the line is first opened. This method is from the 700/900 brake service manual.
<=================End of earlier critique
If I knew of a convincing reason for brake hose clamping, I might try it (reluctantly). But this FAQ offered magazine tip doesn't convince me in the least. And I hope you will try the "pedal down" method the next time you have to open a brake line, instead of clamping it.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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Well the last time I changed pads I used the method described in the FAQ, since then I have also replaced the brake hoses so, I guess I don't need to worry about any possible damage to the hoses that were clamped since they went in the trash awhile back.
While the original quote may be from a magazine it did wind up in the Brickboard FAQ. Like I said before, I realize that not all the methods and practices I read in posts are something I'll use, I think that what I read in the FAQ should be the best generally approved information that is available.
I suppose it boils down to credibility, What I read in posts I think about and possibly question because sometimes the info is questionable. What I read in the FAQ I would like to think accurate or the methods have proven success.
I don't want anyone to be offended when I say I've seem things here that are IMO questionable. The vast majority of what I see here is great. I've been helped out of situations that had me baffled a few times. I've learned alot and saved some money along the way. There are other Volvo boards out there where the BS is flying around so much that you just get used to it while your there, but this is where I go to get straight answers from knowledgable folks.
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"What I read in the FAQ I would like to think accurate or the methods have proven success."
I'd like to think that too. Overall it's a great resource, but I'm afraid some "questionable" FAQ items have been accepted on faith. That magazine tip on hose pinching being perhaps the most flagrant example—with pinching a hose to prevent fluid escaping on a caliper change being right up there too. Especially when the method I cited is right there in the 700/900 Greenbook (as pointed out).
If hose pinching still makes sense to you, despite my reasons to dispute it, well then it's your call. And yes, there is a lot to be questioned in the general responses as well.
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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I'm familiar with your posts, and thats one of the reasons this info is bothering me, Based on what I've seen in the past I think your probably correct. I even wondered if clamping my brake hoses was going to damage them while I was doing it but I figured "this is how it tells me to do it, possibly the lesser of two evils"
If it were someone else I wasn't familiar with I would probably blow-off an opinion that disagrees with the FAQ, now I'm questioning the FAQ.
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"this is how it tells me to do it, possibly the lesser of two evils"
I appreciate your dilemma and near vote of confidence.
My view simply boils down to:
"This" how-to is from a magazine "tip", suggesting that with the bleeder open, retracting the piston(s) could push fluid and possible crud several feet upstream—through an already filled line to an already filled ABS modulator, which connects to an already filled master cylinder.
IMO, the source is not credible and the suggestion is not possible.
How could said crud head in that direction with an open bleeder downstream?
Let's call it a dead horse draw.
Bruce
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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All I can say is "WOW!!". I have never pinched a brake hose, seen another technician pinch a brake hose, seen a bulletin warning about it, or been advised to do otherwise while attending countless Volvo classes. Volvo techs simply squeeze the pistons back into the caliper and be done with it. There is no ill effect on the brake modulator, no glowing ABS lights. Drive the brake pad retaining pins out, remove the spring, take a large screwdriver and compress the piston on one side, install new pad, compress the other side with the screwdriver, replace the pad, reinstall the spring and pins, remove the caliper assembly, remove the rotor, replace the rotor, replace the caliper, put the wheel back on, repeat on other side. The only three things you need to do outside of that are put a rag over the top of the master cylinder, flush the brakes if it has been more than a couple of years or 15K, and pump the brake pedal when you are done and before you drive off. My information is based on 15 years as a Volvo master tech and another 10 years owning and running my own independent Volvo repair shop not something I read about in a FAQ file on the internet or heard at a Ford symposium. Not that there are not cars out there that can be damaged by doing it that way but trust me your faithful old red engine Volvo is not one of them.
Mark
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Hi Guys,
Makes me want to go outside right now and overhaul my brakes. Such passion and knowledge. Great stuff!
Marty
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I guess it just bugs me when I think I've done my home work and completed an assignment correctly and my final grade winds up being a C- because the textbook was wrong.
As far as passion goes, I've been accused many times of having too much when it comes to my Volvo, I rarely am accused of having too much knowledge, Volvo or otherwise.
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