Hi guys, have just had to replace the solid and flexi lines on my C4, everything went to plan there, but on bleeding the system as per Adrians book I am left with what I think is an un-usual pedal feel.
When I put my foot down it sinks with very little resistance about an inch or so then goes very hard, but if I keep the pressure on it eventually sinks to the floor.

Is this right or should I be concerned?

TIA

 

I'm not familiar with the process in Adrian's book but opening up lines, removing calipers, etc. usually requires a complete flush to regain firm pedal feel, i.e. 2 liters of fresh fluid. Pedal feel should be fairly firm as you push down an inch or two--going to the floor suggests you need to keep bleeding.

 

I have bled through about 4 litres so far and am getting no air whatsoever!

 

C2 or C4?
4 litres should have been enough, if you pumped the pedal to bleed there might be damage to master cylinder seal.
Have you checked all your new connections for a leak.

Sorry thats all I got.

 

Hmmm. 4 liters should've done the trick.

What is this "process" in Adrian's book? When I bleed/flush, it's pretty straightforward: add fluid, pressurize system, bleed both valves, move to next caliper. Reservoir is alway at or near Max fill line and I go in the recommended order: RR, LR, RF, LF. Repeat until pedal is firm. Is it much different?

I've also sent a note to Garrett376 to see if he might be able to offer some (better) assistance.

 

I had the same problem when I replaced my brake lines. I put about 3 litres through and still had a terrible pedal. Took it to the shop and we bled the ABS resevoir (the ball looking thing on the right side of the front trunk) and that salved the whole problem.

I would invest in a power bleeder, well worth the $50!!! makes brake jobs a sinch and much faster. Also on a C4 it is a must what with all four calipers, both diff. locks, and the ABS system. Oh and the slave, can't forget that.

Good luck.

 

how are you bleeding the system - your methods are not described so it's hard to help... using the foot pedal? using a power/pressure bleeder?

The diff locks and PDAS components are not affected when you do something on the brake side.

 

Hi all, and thanks for the input so far.

It is a C4 which I have bled using a pressure bleeder starting at the rear and working forward making sure to do both nipples on each caliper.
I have also bled the abs system including the sphere and solenoids all by the book.
Am really wondering if the seal in the master cylinder has bought it??

 

I presume at some point when bleeding you had to press the pedal (e.g. to move the pads back to the discs). In which case, did you press the pedal all the way to the floor while doing it? This can cause the master cylinder to stick (happened to me once). I managed to get mine working again by pushing the pads all the way back and then used halfway presses on the pedal until the pads went back to the disc and the pedal firmed up again.

 

I hate bleedin brakes, no fun at all.
Ive done it on the flash twice, after changin all the lines/pipes.
Last time i had the mech do it, a lot less stress.

You may of done a seal on the master cylinder, they can turn or twist if operated without the correct amount of fluid.

This happened with my golf when the caliper leaked, needed a new master cyl.

 

I have had that happen too and here's what I did:

1. finish flush with no air bubbles coming out
2. key to accessory position - first click (not running)
3. wait for high pressure pump to stop running
4. pump pedal several times until soft then stop, go to step 3
5. repeat 3 and 4 for several minutes
6. start car
7. repeat 3 and 4 a couple of times and you're done

For some reason this works - unless you start the car, the high pressure pump never seems to stop running after you pump the pedal a few times. As soon as you start the car, the pump seems happy.

Hope it helps.

Marc

 

Pressing the pedal when bleeding a C4 is apparantly a big NO NO, so I left it alone and just used the pressure bleeder.

 

Yes it is. I don't do pedal bleeding on my C2 either. I was referring to using the pedal to move the pads back to the disc or checking the pedal pressure, which you obviously would not do with bleed valves open.

 

Well, I tried Marc's idea out and all seemed ok to start with, the pedal went quite firm. I then left the car to idle for a moment or two and when I tried the pedal it went straight to the floor.
Does this sound like a master cylinder problem to you guys???

 

Well, my simple logic is: if there are no external fluid leaks (inc around the reservoir), then the pedal movement results from a master cylinder internal leak. Brake fluid will not compress, so if no external leaks show, then the fliuid is not going anywhere. If there is air in the system, the pedal will be spongey part of the way until the air is compressed. If the pedal reaches the floor under constant pressure, then the m/c needs fixing. Had this 2 yrs ago on a different car after refurbing all the brakes.