Soft brake pedal after caliper replacement - 06 V50 T5 AWD

[scot850]

My friend has a 06 V50 T5 AWD. He has been having a real problem with his brakes. His car is now on the 4th LHR brake caliper. The original corroded and swelled up preventing the pistons from pushing the pads.

He replaced it with a cheap re-man but could not get it to bleed even after replacing the flexi-hose to it. I had a look at it and figured out the reman unit was junk as you could not get fluid through it.

He replaced it with a Nugeon branded one which I like their products, but this one after fitting and working nicely, started leaking from the parking brake shaft seal badly. Due to time constraints he went to the junk yard and pulled a used on today. He and a buddy of his fitted but cannot get a firm pedal. They even tried running the engine while bleeding the system to make sure the pump was enabled. What I don't know is if it even works.

Is their any suggestions on where to look? Could it be the hydraulic pump not functioning or running weakly?

Any suggestions greatly appreciated. I will no doubt get it to look at it a few days so I would like to be prepped!

Neil.

[Vova585]

1. I would inspect the last caliper. Make sure there is no fluid leak.
2. Make sure pads installed correctly and clean(who knows, maybe they were in rush and missed something basic)
3. Would take a torque wrench and check bracket and caliper torque(likely 120nm and 35nm).
4. Make sure he used correct brake fluid and not something old or not correct spec.
If above checked and good(which highly likely it is). I would go to vida ar alldata and read about proper procedure to bleed the system including abs pump. It will likely require pressure bleeder and dice/capable scanner able to command the abs pump. It is possible that system "sucked air" during all those manipulations.
Another solution- pay dealer $250 for brake fluid flush/bleed.

[scot850]

I have a pressure bleeder and a Vida/Dice system so can look into that. Never used that function as I have never needed it. It will be a learning experience.

What about the hydraulic pump not working properly? I recall having to have on replaced on or son's XC70 when it had less than 100kkm on it under warranty at the dealer. That was about 15 years ago so I recall the pedal being soft and almost going to the floor.

Neil.

[Vova585]

I would doubt. Issue started after caliper was replaced numerous times. I would start with basics and hope for the best.

[scot850]

I agree. Poor young guy is sick so once he is better we can look at it and update how we got on. Thanks again.

My ex-Volvo mechanic buddy said the same thing as you.

Neil.

[scot850]

The V50 arrived yesterday (Saturday) noon, and we took all 4 wheels off with the car on the hoist. Fitted the pressure bleeder after removing one front brake caliper that had been fitted with the hose twisted. Then started bleeding the brakes. First one (RHR) no fluid cam out. Pulled the brake bleeder and it was blocked. Swapped with a good spare and then bled it. Some air bubbles came out so progress. Then tackled the LHR. It bled fine but no air bubbles. RHF, loads of air. Finally LHF. Again no air. Checked the pedal and firm. Started the car and tested the pedal and felt like still had a bit of air. Ran more brake fluid through and no more air except a little from the LHF. Pedal now hard. Great, now there was a drivable car. Wheels back on and off he went. Called me when he got home to say brakes were working much better but still felt there was a dead pedal for about the first 15mm of travel. He was going to drive it again later and see if the system burped any more. He then planned to try and bleed the brakes again himself and see if any more air comes out.

If that does not work he will come back with the car and we can try Vida and see if we can figure out how to get the ABS to self bleed. If that does not work I will see if the Mucar bluetooth unit and software can do bo-directional operations on the ABS.

Neil.