Brakes are soft with no stopping power + wheel jerks to the left when braking

[BrokeInCollege]

Hello everyone, this is my first post here so bear with me and let me know if I messed up any post formatting

I recently purchased a 1998 S70 GLT to take with me into my second year at Uni. Got it for a good price and Im fixing up all of its issues. Ive taken care of tons of stuff so far but this issue has stumped me.

The brakes are very soft, and it feels like the top 1inch of the depress does absolutely nothing. When you fully press the brake, the pedal seems to stop short of where it should actually stop at. Furthermore, when I am going above 35MPH (not sure what that is in KPH) and I depress the brakes about halfway, the steering wheel jerks hard to the left and will stay turned about 4 inches or 30 degrees from center while the car continues to go straight.

Heres what I’ve done to try and troubleshoot:

Bleeding the brakes -> the front passenger brake bleeds perfectly, the front driver’s side bleeds with some stutters, and both rear brakes just dont. Barely any fluid out of them, and when I connect one of those vacuum brake bleeders, I cant even pull a vaccum after endless pumping

Steering rack and power steering pump/lines -> replaced and working perfectly

Brake pads/rotors -> some replaced but some were in good shape so I left those few. On the inside of front passengers side tire, there was a huge amount of sludge sprayed everywhere, including under the shock and around the caliper. I cleaned it up and as of a few days it hasn't seemed to come back. I checked all of the brake lines and they are in perfect condition. Potential suspension issue there?

ABS module -> serviced old one and replaced. I previously had ABS/TRACS lights on and no speedo and the repaired module fixed those issues. Granted that was only 1 day from writing this post so maybe the brakes haven't responded yet?

Tires -> one of the front tires is in pretty bad shape and definitely needs replacing soon, however it still holds pressure okay enough where i dont think that could be the cause for the super aggressive jerking

Other info: there was a check engine light when i got the car, which was for the steering pump and ABS module I believe. After fixing both the light is still on. Not sure if that plays a role. The steering itself works perfectly however there is some creaking when turning very hard, however the car is still very stable on bumps and turns
*edit* adding in the fact that both of the calipers are completely rusted over. They do work, as I can hear and see them move, however I cant say how well

Thank you guys so much for reading this stupid info dump, I wish I could be more specific with naming just one problem. I am just extremely stumped and hoping someone can point me in the right direction as I have legitimately no clue how to diagnose. Thanks again everyone

If anyone needs photos of you name it, I will totally provide them

[volvolugnut]

I will guess that your front driver side brake caliper is leaking and has sludge internally. The mess you cleaned if likely leaked brake fluid. These can be rebuilt, but it is hard to get parts. The rear may have the same problems.
Best, cheap plan is a good used caliper from the same model car. Be sure to get with the same brake disc diameter. A rebuilt cylinder is also an option.
The current driver side brake disc and pads are likely oil soaked. Clean with brake cleaner or replace both discs and pads. Do not heat brake cleaner - it can kill you.
Replace brake parts on both sides for balanced braking.
When you get a brake caliper that can be bleed properly and flush fluid, you should get smooth braking without the jerk to the side.
Steering noise is likely suspension parts needing replacement.
Your cheap Volvo is getting more expensive.
volvolugnut

[scot850]

All P80 calipers are the same, 280mm and 302mm rotors use the same calipers, but different mounting brackets. They also use different length flexi-hoses with the 302mm rotor caliper having longer flexi's.

Volvolugnut has covered all the basis. Only addition would be the flexi hoses can collapse internally causing sticky brakes but look fine on the outside.

Neil.

[BrokeInCollege]

I will guess that your front driver side brake caliper is leaking and has sludge internally. The mess you cleaned if likely leaked brake fluid. These can be rebuilt, but it is hard to get parts. The rear may have the same problems.
Best, cheap plan is a good used caliper from the same model car. Be sure to get with the same brake disc diameter. A rebuilt cylinder is also an option.
The current driver side brake disc and pads are likely oil soaked. Clean with brake cleaner or replace both discs and pads. Do not heat brake cleaner - it can kill you.
Replace brake parts on both sides for balanced braking.
When you get a brake caliper that can be bleed properly and flush fluid, you should get smooth braking without the jerk to the side.
Steering noise is likely suspension parts needing replacement.
Your cheap Volvo is getting more expensive.
volvolugnut

I will try cleaning them up first as you suggested, and Ill disassemble the calipers to get a good look at them. I went back out to try bleeding the brakes again, this time with the car running. With the engine on, the rear brakes get great flow of fluid and pressure. I checked both rear brakes and they were great while the car was on. I am almost certain there is no leak in the brake lines as for the last two weeks of observing the brakes, I have seen no dips in fluid or any puddles on the ground (Besides the sludge in the pass wheel, however that has still not returned so I'm not sure)

Could this be an issue with the master cylinder? Or whatever that metal block beneath it is?

[jmartin919]

The noise may be stearing stops needing grease.

[BrokeInCollege]

In case anyone is following this in the future, Ill be updating with my attempts and potential solutions. In the last few hours ive dumped half a can of brake cleaner onto the front and back of the rotors and that fixed about 75% of the wheel jerk and braking distance. I now suspect that the front rotors are either misaligned or the brake pads I thought were okay, were actual piles of shite. Will replace rotors and brake pads soon and update again.

[volvolugnut]

I don't see that you have checked for codes with a scanner. If you do not have a scanner, go to one of the chain auto parts stores and have them scan. WRITE down ALL the codes then try to clear them. Clearing is needed to turn off the check engine light.
If the codes stay cleared for 100 miles or so you likely fixed the problem.
volvolugnut

[scot850]

There is a plastic one way valve in the booster. They do fail with age. Often they will give a soft pedal.

Can you borrow a pressure bleeder? If air gets stuck in the ABS pump it can be hard to move out.

Neil.

[BrokeInCollege]

I don't see that you have checked for codes with a scanner. If you do not have a scanner, go to one of the chain auto parts stores and have them scan. WRITE down ALL the codes then try to clear them. Clearing is needed to turn off the check engine light. If the codes stay cleared for 100 miles or so you likely fixed the problem. volvolugnut

I swear I am not new to car maintenance, but I admit I completely ignored scanning the car again after my repairs. Thank you for this! I found my trusty Ultragauge and hooked that up and was greeted with a P0455 code and nothing else. A friends scanner confirmed this code. From my understanding this is a vacuum problem dealing with the fuel lines? I will make sure to check the fuel cap tomorrow. Regardless no brake/abs related codes.

There is a plastic one way valve in the booster. They do fail with age. Often they will give a soft pedal.

Can you borrow a pressure bleeder? If air gets stuck in the ABS pump it can be hard to move out.

Neil.

I will definitely look into this. Would I bleed the air through the bleeder screws on the caliper or from the metal brake lines going into the master cylinder? I already tried bleeding though the calipers but clearly there are a bunch of other things I could try. Thank you so much!

[scot850]

With a pressure bleeder you should be able to bleed through the caliper bleeders as normal Start at the furthest away rear one (RHR) and work forward from there.

The pressure bleeder adds pressure to the brake fluid reservoir, no need to pump the brake pedal. One person operation, just make sure to keep checking the reservoir has fluid.

Neil.