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Bleeding brakes after MC change, with PSM

MisterCorn

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8 Jan 2011
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9,410
I am ready to put some brake fluid in my car. The master cylinder has been changed along with various other pipes, so there isn't a lot of fluid in the car. It is a 2001 model with PSM. My usual technique is to fill the reservoir and then have somebody press the pedal whilst I open and close the bleed valves. Starting furthest away and working back towards the front right

I have read that cars with PSM need to use a special technique. I have a durametric pro which I think might be able to do what is asked for, but the issue is that I don't want to put power on the car as it is pieces. Any reason to think I can't just bleed this way for now.

The car is only going to be pushed around at walking pace, so in reality it would be fine on just the handbrake, I just want to test the brake system anyway.

I am going to go with ATE TYPE200 fluid.

Thoughts and opinions appreciated.

MC
 
Buy a Gunson Eezibleed for £20 to make the task much easier, quicker and single person, great tool to have.

Demort made some informative comments on brake bleeding recently, I think it was on the brake line over engine thread which might be of interest.
 
Mine has PSM and drained when I changed all the front pipes incl the transverse one above the rack.

I read lots about operating the PSM valve whilst bleeding so planned to take it into GCR central in Leicester. When I spoke to them they said they just bleed them as normal without valve operation. That was 8 months ago and brakes been fine.

The other thing I read, after I'd bled the brakes!!, was with a used mastercylinder when bleeding the traditional way don't push the pedal to the floor as the seals could get damaged on an unused bit / lip in the bore. New MC or eazibleed would not be an issue.

Also found the bleed sequence via google and there is a difference between PSM and Non PSM.

Just bleed them as you would on any other car for now and do the PSM valve thing (if you feel necessary) once all back together.

Ian
 
Thanks Ian, That has confirmed my thoughts.

MC
 
I couldnt get a decent pedal with and easibleed when I did my brake lines front to back and over gearbox.

The easibleed pushes fluid from the resovoir through the lines.

I had to take it to a local garage who bled it no problem with their vacuum bleeder.

This pulls fluid through from the nipples.

The only reason I can think that I didn't succeed, is maybe the vacuum managed to pull fluid through a different path in the abs pump or something. The garage didn't use a computer either.
 
Paynewright said:
The other thing I read, after I'd bled the brakes!!, was with a used mastercylinder when bleeding the traditional way don't push the pedal to the floor as the seals could get damaged on an unused bit / lip in the bore. New MC or eazibleed would not be an issue.

Really valid point - my background is with Honda CRX's and its common practice to never go more than half way on the pedal on an original cylinder when bleeding or you WILL destroy the seals.
 
Just get some fluid in it and bleed on the pedal for the time being just to move it to paint and back, there will be enough stopping power, I can't see you getting much over the national speed limit from your workshop to the paint shop.

Personally I would want to get some fluid in there so you can to sap any moisture in the pipework and calipers over the next couple of months, then when you are ready to bleed it properly make sure you get all the temporary fluid out.

I have had an Easybleed for years but only used it once, when I first bought it, the pedal method has always been best. Think I used it couple of times for the clutch though.
 
If you are replacing the PSM unit or you have drained it .. not sure how ..then you will need a tester to open the valves in it to bleed it .

I think from memory ive only dont this once when replaceing said unit .

Either way its pretty obvious .. you wont have a brake pedal basically if there is air in the PSM .

Full pedal bleeding .. its normally ok on a 996 .. but to be fair we use a pressure bleeder and only revert to this if there is a problem .
 
Bleed it as normal for now (I use pressurised cap on reservoir and also push through with pedal). I don't think the fluid (or lack of) in the ABS valves will cause you any issues just shunting it around. You'll be able to tell immediately if you're ok anyway just with brake pedal feel.

Obviously before going out on the road you'd want a full bleed with the durametric
 

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