Brake Bleed Cayman

[Mike D'Silva]

so after I fitted new rotors, pads and sensors, I thought it wise to do a brake flush too.

 

I used a Vacuum bleeder... out came the old Green fluid... in went some boring yellow fluid.

I did, left rear, right rear, left front, right front...

 

After doing this, i felt that even though the car brakes fine, the pedal feels a little spongy... has to be air in the system.

 

Bleed again, but exactly the same feel.

 

So then I try a Pressure Bleeder...the local independent said they use a pressure bleeder as they seem to work better for these cars...

 

Put some nice Motul RBF600 in... and away we go.

 

This time, some of the original green fluid still came out! I dont know where it was hiding.. 

Same sequence.... also, did the outer nipples, then the inners.

 

Brake pedal still feels the same.

 

I read somewhere then activating the ABS helps to bleed it...??? so i try that... ABS works great, brake pedal still the same.

 

Finally, I tried the tried and tested, 2 man job... pump pump pump, crack the nipple, etc..

I little air came out the first nipple, but after that, solid fluid everywhere.

 

Pedal still feels spongy... but let me explain it fully.

 

With the engine off, and pumping the pedal, it gets rock hard.

 

Start the engine, and it softens....

With it still running and stationary, if I pump it up a few times, it gets firm again, but if I keep my foot on the pedal, my foot slowly goes in with the pedal....then it is soft and spongy again.

 

The car has done 30000kms...

 

Any ideas?

Mike

[wasserkuhl]

Get some flat wood that is thinner than the brake pads. Say about 8mm thick. Cut to size of the pads.

 

Remove the brake pads, (one caliper at a time), and replace with the wood. Bleed that caliper. Then lever the pistons back and re-install the pads. Move to the next caliper.

 

Do one wheel at a time.

 

Your spongy-ness should go away. However you may need to bleed a few more times to get it to optimum. 

 

A pressure bleeder may work on most occasions, however there is no substitute to having someone press the pedal and you bleed.

 

I have done this on several occasions and it worked.

 

I would also suggest checking the flexible brake lines to each caliper, just in case they are "ballooning".

 

Also, please ensure you are using DOT 4(or greater) brake fluid.

 

You may well have to bleed the brakes with the engine running as well.

[Russ]

my 2c:

 

ABS should just go "over the top" of your brakes so to speak - it shouldn't affect how you bleed them

 

if it's firming up the pedal with the engine running it sounds like a vacuum leak on your brake booster

if it's firming up the pedal with the engine off it's normally air in the lines

 

I think your flexible lines should still be fine, the car is still relatively new

 

but +1 to what wasser said too.

[Kelly]

I experienced similar situations with my 996 in the past. I had to do multiple pressure bleeds with drives and multiple abs activations at low speed on a gravelly car park. The abs activations move fluid through the abs hydraulics/valves and help to move bubbles into the main lines for subsequent flushing. I ended up putting a lot of cheap fluid through the system to get it flushed and a hard pedal. Then I re flushed it with SRF to get the fluid performance I needed. Definitely incorporate some old style pedal flushing into the routine.