1998 V70r, Front Brakes Minimal/ No Wear - Heavy Wear Rear??

icrashcars · Post by **icrashcars** » 10 Nov 2016, 17:47

I know these cars infamously go through rear brakes more quickly. However, I have gone through 2 sets of rear pads and the front looks new.

I bled the brakes about 30k miles ago during the full brake service (f/r pads/rotors, new fluid). The braking seemed weak. So I fully bled the system a 2nd time...no bubbles. (used power bleeder both times)

Chalked it up to weak brakes on the car since i had nothing to compare it to. (my other vehicles run BBKs)

About 10k miles ago the rear pads were shot, rotors looked good so i just swapped the pads since I planned a full R&R soon.

A few days ago the rear pads sounded cooked again, checked and they are down to metal.

Just put on new rear pads/ rotors and went to do the fronts and they look brand new (30k miles on them).

Had someone press brake pedal while I had a front caliper off and the piston extends fine.

So I just bled the fronts and no air.

What am I missing?!

Post by **erikv11** » 10 Nov 2016, 21:27

Don't know but I am curious. I haven't experienced that the rears wear out much more quickly than the fronts.

What brand(s) pads are you using and what material, front and rear? E.g. I wonder if you have metallic (even organic?) on the rear, ceramic on the fronts.

The OEM front pads are beveled, that likely makes them wear out a little faster. The OEM pads are also semi-metallic, FWIW.

Post by **abscate** » 10 Nov 2016, 22:01

Your rear calipers are rusted and sticking. You will burn out brakes really quickly

Consider rebuilt ones from Cardone...usually built on a ATE cores which are OEM

In edit ...fixed typo, thanks Erik

Post by **erikv11** » 10 Nov 2016, 23:40

Typo alert: on ATE cores. NAPA sells those, too.

Post by **Clemens** » 11 Nov 2016, 00:24

I'm thinking stuck rear calipers too. They might work but not release properly. Had that on both of our 850ies. Are the rear brake pads worn evenly?

Post by **abscate** » 11 Nov 2016, 03:48

I haven't experienced short rear brake pad life on my 1999. I think I am on my third set of pads at 185k miles, replaced about 10 k miles ago. 85k life isn't too bad

Post by **cn90** » 11 Nov 2016, 06:14

Warning: the metal line that joins at the Rear caliper is a gamble, sometimes it comes out but very often it is seized and you will round the nut.

My advice (I think your rear caliper seized) is:
- Check the rubber boot, if torn, your piston is rusty, this causes it to stick.
- Rebuild the caliper in situ by either:
A. Using a rebuild kit (info in forum) or
B. Transferring parts from the NAPA rebuilt caliper over (piston, seal, boot). If you do it this say, you will avoid the frustration of the seized nut!

icrashcars · Post by **icrashcars** » 11 Nov 2016, 06:44

Thanks. Ill check the rear calipers more thoroughly, and rebuild/ replace if necessary.

Someone also suggested doing the brake lines while I am at it since they are 18 years old...thoughts?

Rear pads are worn dead even.

Had matching pads/ rotors on front/ rear (ceramic and drilled).

Switching to non-OEM semi metallic and standard rotors.

Post by **cn90** » 11 Nov 2016, 08:44

There are 4 rubber brake hoses.
- Front 2 hoses are relatively easy.
- Rear hose s x2:
a. The left rear hose is somewhat difficult but should not be too bad.
b. The hose above the delta link: close to impossible to replace in situ. Unless it leaks, leave it alone b/c it is not subject to too much flexing.
Replace it when you have a chance to lower the delta links (such as replacing the rear ball joints).

Anyway, I find propane torch to be my friend. I wrote a lengthy brake hydraulic repair below:

https://www.matthewsvolvosite.com/forums ... =1&t=37721

Post by **erikv11** » 11 Nov 2016, 09:00

You're going to want to hear from from other AWD owners who have actually worked on this setup, about their opinion of how difficult the brake line access is. The FWD and AWD cars have very different rear ends, including brake lines. Neil (Scot850) has done pretty much everything to the rear of a P80 AWD, hopefully he will chime in.

If you do replace them, make sure to buy high quality lines, like from ATE or even Volvo.

Accessing the lines is the crux of the job. I've never had a rear hose leak or fail ever, on any of my P80 Volvos. Like cn90 said they don't have to flex every time you turn the steering wheel. That said, I have replaced them a couple times just because they looked like they were in trouble. So for sure give them a look for dry rot cracking and to get an idea of access, then in the end it's your call. On the FWD cars it's easier to replace the hose on the delta link if you remove the bracket that attaches it to the rear trailing arm, before you try to unscrew the hose.

The flare nut connections at the caliper and the brake hoses will likely look pretty bad (rusty and corroded) on the rear of a NY car. With heat and good penetrating oil, lots of wire brushing beforehand and good quality flare nut wrenches I have always been just fine disconnecting these, but for sure be really careful to not round the nuts on the hard lines.