Rear Brakes not engaging

[Grantkat]

1999 s70 GLT. based upon a visual inspection today at work, neither rear brake is engaging the rotor. Pretty obvious, front rotors shiney and hot, rear rotors rusty spotted and not hot (warm at best).
So.....here is my thought on diagnosing after reading several posts.

I need to check and see if the pistons are frozen
1) loosen the bleeder and hit the brakes and see if i get fluid coming out. if fluid ejects go to step 2. if no fluid, then the problem farther back in the line/brake system somewhere.
2) remove caliper from the rotor and pull the pads off. hit the brakes and see if the piston moves. no movement = stuck

if the problem is no fluid when braking, what now? - how best to troubleshoot that and what I am looking for?

[yanga001]

If you have the wheel off you might as well grease the slider pins on the pistons and check the wear of the pads. Slightly seized pistons will normally wear out one side faster.

Fluid will come out of the bleeder regardless, hydraulic force is significant and it will follow path of least resistance.

You can also bleed the whole system to help.

My partner’s car had old calipers that were hard to bleed and we just replaced them all with raybestos ones and greased it. The car now locks up properly when you need it too.

A good bleed goes a long way as well.

Also my partner’s car had one caliper replaced early and it still had rust/uneven wear on the rears. New pads and rotors fixed that as well.

[abscate]

stick a thin piece of wood in both sides of the rotor if you hit the pedal with the pads out. I am pretty sure the rear calipers will psuh both pistons out and blow fluid everywhere without oads.

I would have two new calipers in hand once I committed to opening the brake system, if it is that locked up it needs new stuff.

[scot850]

Also replace any flexi brake hoses at the rear.

Neil.

[Grantkat]

Thanks guys. Due to the outdoor temps and of course work I havent had a chance to work on it, but I am about 99% sure its a caliper issue, either pins or pistons or both. I think I will go the route of new parts/flex lines. I agree with abscate/neil. there is zero harm and tons of upside to replacement. I will keep you posted and let you know exactly what i find.

[scot850]

In all of my Volvo owning years in areas where the roads are salted, the rears have usually failed before the fronts by seizing.

Good Luck!

Neil.

[jreed]

I have had OK luck (about 18 months so far with no issues noted) with NAPA Adaptive One calipers on the rear of my car.
There is a helpful write-up on brake caliper issues/repairs here: viewtopic.php?t=102449

[scot850]

They look like a good reman unit. I like Nugeon as up here they are cheaper but well coated in their higher quality option. Napa stuff up here is getting really silly priced for some reason.

Neil.