2300cc

According to the shop manual, when bleeding brakes on cars with PSM you should have a bleeding pressure of 2.0 Bar (29.4 PSI). Is it necessary to use this much pressure? I have a motive bleeder. Thanks.

Dharn55

You need the Durametric (latest version) or the Porsche system to bleed the ABS.

redridge

according to Rentech... you should NOT go over 20psi.... anything over can cause damage. PSM is more of the system.... but are you talking about ABS?

2300cc

No, i am talking about PSM, I am just reading the shop manual and it state scars w/o PSM should be bled with 1.5 bar of pressure and cars with PSM should be bled with 2.0bar of pressure. I read the rentech DIY as well and thats why I was asking. If everyone has done it using under 20psi that is the route I will go. Thanks.

redridge

Ive had no prob bleeding the brake lines at 20 psi... per rentech diy. But I have done mine in warmer weather... dont know how the fluid reacts in the cold....

LVDell

I bleed all mine at 1.5bar or less (usually 1-1.25bar) regardless of PSM or not. I have zero issues having the fluid flow properly. Would be interested to hear to reasoning for bumping up to 2bar on PSM cars.

Can you scan and post the shop manual page(s) you are talking about?

2300cc

Here are a couple of screen shots.

LVDell

Interesting, and it also shows a different sequence of bleeding when getting to the fronts. Very odd.

Thanks for posting.

Robin 993DX

Sequence to the front is from left to front based on the SM, how is that different from what it is normally done?

LVDell

Robin, look a little more closely.

They show RR/RL/FR/FL for the cars without PSM
...and........RR/RL/FL/FR for the cars with PSM

Sneaky Pete

On my '99 C4 with PSM I bled RR, LR, RF and LF in that order. LF silver caliper turned gold after the 1st DE last year. Related?

redridge

possibly related more from your headlights....

Robin 993DX

You are right!

I did it the old fashion way many times, didn't notice any difference with my brake performance. But now I think about it my PSM does not react as fast as before... maybe 0.01 seconds slower. :P

Sneaky Pete

I think your right......still makes me wonder though. Why would the sequence be different with PSM?

LVDell

Alight, anybody with the reason why it is different between psm/non-psm cars please chime in!