Brake system questions Topic is solved

[abscate]

How are you measuring brake pressure?

I will use the SSBC A1704 Brake Pressure Gauge Kit. I haven't used it yet, but apparently it works great. Check YouTube for usage videos, including tips to minimize air in the gauge. Also note that, according to reviews, the plastic face of the dial gets corroded by brake fluid (bad design choice) so be very careful with it.

Hopefully this will answer the question of why my rear calipers haven't been clamping down on the rotors for the past 3-4 years.

please post that caliper rebuild link. Im pretty sure im getting due for this, pad is hanging up and i can hear squealing around turns and when pedal lightly depsressed

See the caliper rebuild tutorial by CN90. It matches what jimmy57 said above, but with pictures. I took apart my front caliper and you won't believe what I found. After reassembling it with the old (yet intact) seal, the seal popped off as soon as I depressed the brake pedal. I had to take it apart and reassemble it again. I haven't checked to see if the seal came off again, but I will report back if it did. Then again, I was working with a pretty rusty caliper, so it may have been doomed to fail.

I just harvested two good calipers off the 1998 V70 - Where are you in NH? Might be up there next weekend?

[PeteB]

Hopefully this will answer the question of why my rear calipers haven't been clamping down on the rotors for the past 3-4 years

I had rear calipers on another car that would not bleed, asked around and learned that the flex
hoses can become clogged on very old cars. Replaced them and all was back to normal.
The hole is tiny since you need wall thickness due to the high pressure.

We've had extensive problems with the rear calipers on our 850 and I recently replaced the
hoses on the theory that they were partially blocked such that they took a long time to release.
Dragging caused them to overheat. Here's a thread where I document the 2nd or 3rd attempt
at fixing them:
viewtopic.php?f=1&t=81876

viewtopic.php?f=1&t=81875

I think that I have a few more threads out there on brake problems.

[FireFox31]

Here's a thread where I document the 2nd or 3rd attempt at fixing them:

Thanks for replying here. Your caliper thread taught me a lot when I started this project. I hadn't seen the rear hose thread, so thanks for linking it and posting such good pictures.

What ultimately fixed your rear calipers? Did the new hoses allow the pedal to fully depress when bleeding?

[PeteB]

The bleeding problem was on another car and yes on that car replacing the hoses fixed it.
Edit: just reread my thread on our 850 hoses and I was having a problem where the pedal would not go all the way down on one side, and there was only a small drip. Yes, the new hoses fixed that problem and it bleeds normally now.

The problem with our 850, I believe, was that the hoses being partially clogged (theory)
caused brake drag and overheating. I've not had to work on them since that repair so we'll
see next time I take a look.

While I don't like doing jobs over again, it was nice getting free replacement calipers from FCP.

[abscate]

My aftermarket rear calipers locked up tight in 2 years., Piston was completely frozen in the caliper. There had to be a failure of the piston boot (not the seal) to let salt water into that assembly, plus Im guessing the piston metal was silver Cheese - aka Chinesium.