E38 soft brake pedal doing my head in

[voodoomelon]

Right so I might be making some progress, got a full set of Brembo pads for all corners and swapped them out today.

The two pistons on the inside of both of the front calipers were INCREDIBLY hard to push back into place. I had to pry them back in using the old brake pads with a massive screwdriver to get as much leverage as I could. This is in comparison to the outer two pistons on both sides of the car which just pushed in like a breeze.

Same went for the rear caliper pistons, no problems.
The inner pads were more worn than the outer ones so the pistons were no doubt sticking.











New pads are in, the car is still on stands but after bleeding the pedal does feel a bit better already, albeit not perfect.
I'm going to stick the wheels back on and take it for a spin and see what's what.

The question is, can sticking pistons give a soft brake pedal? The ABS unit is still making that squelching noise so I still think something is amiss there.

[Super4]

Its hard to see in that photo but if the pads were more on the inside than the outside then its very possible they have been glazed badly due to heat and thus rendering them near useless when braking. Was there any sort of a crunching sound or cracking sound when pushing the inside pistons back in? If so then they could very well be seriously rusted and pitted in behind them and thus need replacing. It would be well worth taking a caliper off and taking it apart to see the state of them.

[voodoomelon]

No there was no noise pushing them in at all. Whilst it took serious effort to get them back in, they went in without a sound.
Thing is, the soft pedal was there when the car was completely stationary, so I doubt the pads themselves were an issue. Just wondering if stuck pistons can give that feel.

[318is-joe]

did you ever get to the bottom of this?

[voodoomelon]

Realised I never posted an update on this, yep definitely got the brakes better. After I changed the pads and pushed all the pistons back in, and rebled the system twice more, its better. I think the front calipers were the issue. Shes still not anywhere near as rock hard as my E66, but they stop the car and stomping on them stops it on a dime. ABS etc all works. Its still soft, but the question is am I judging them fairly compared to a much newer more powerful car.

I'm happy with them as they are anyhow, the restoration is just finished, will post some pics up.

[318is-joe]

Glad it got better. Out of interest with the re bleed etc has the squelching sound disappeared from the ABS module

[voodoomelon]

I never checked to be honest now that they're working, when i've another man around i'll check.