C4 pressurised brake bleeder.
08-16-2014, 06:14 PM
#16
Rennlist Member
Theres a lot more than just the brake calipers that need to be bled on the C4's. DIY here: https://rennlist.com/forums/964-foru...procedure.html
You can bleed the 964 brakes fine with vacuum, I have done on my car many times.
I also have a gunson pressure bleeder (readily available in the UK) which I've used when I wanted a bit more oof eg if the system was fully dry.
I however recently changed my views a little and on very old systems I think pressure bleed is safer on old potentially worn out seals than vacuum - I recently had an old ABS unit (not in the 964) spring a leak after vacuum bleeding and I think it's because the old seals could hold the pressure (which they see all the time of course) but not the vacuum.
The 4wd stuff in the frunk can be bled without any special tools (no vacuum or pressure equipment since it supplies it's own pressure) you just need to fully the procedure in Adrian's book. The 4wd locks can be done with or without the bosch "hammer". I have only done them "without", you just have to pressurize the locks but using the **** in the centre console and then crack the bleed nipple, and repeat many times.
I also have a gunson pressure bleeder (readily available in the UK) which I've used when I wanted a bit more oof eg if the system was fully dry.
I however recently changed my views a little and on very old systems I think pressure bleed is safer on old potentially worn out seals than vacuum - I recently had an old ABS unit (not in the 964) spring a leak after vacuum bleeding and I think it's because the old seals could hold the pressure (which they see all the time of course) but not the vacuum.
The 4wd stuff in the frunk can be bled without any special tools (no vacuum or pressure equipment since it supplies it's own pressure) you just need to fully the procedure in Adrian's book. The 4wd locks can be done with or without the bosch "hammer". I have only done them "without", you just have to pressurize the locks but using the **** in the centre console and then crack the bleed nipple, and repeat many times.
Do you know it wouldnt have leaked if you had used pressure as well?
Ill probably buy one but i have one question.
the one linked above sounds great. it has a reservoir so the cars does not run dry. this looks good also but has 42mm cap? one above has 45mm
anyway
So when you have finished ho the hell do you disconnect it? even if you release the pressure in the pump up tank there is still going to be fluid in the pipe or at the very least the reservoir in the car will be full right up to the top of the cap and a little beyond so when you screw off the cap it will go everywhere.
think that's why i gave up with the last one I tried. is there a knack? or am i being thick?
Last edited by Pesty; 08-16-2014 at 06:51 PM.
08-16-2014, 07:11 PM
#17
Three Wheelin'
Can't say for sure but it's a coincidence that it was fine for 25 years then poof. Theory is that basically the seals had failed but in such a way that they could still do their job (they squished into the cavity they were sealing) and I think the vacuum pulled them out of the cavity destroying the remaining seal.
You do need the cap to be the right size, I use the gunson eazibleed and it works fine and is nice and small for storage.
You release the pressure and the fluid mostly gets sucked inthe the pressureised pot. But the reservoir is still brimmed and it can be a little messy and if you forget to disconnect the pressure before removing the cap... yikes.
I tend to use the gunson "dry" for these reasons. You just need to be more careful not to run the reservoir dry.
Another daft thing I did recently was unwittingly pulling the pads out of the calipers while the pressure was connected (god knows how I did it in that order!) Anyhoo I only noticed it had forced the brake pistons out until they clamp directly on the disc when I came back to fit the new pads, that's an interesting one to fix
Ill probably buy one but i have one question.
the one linked above sounds great. it has a reservoir so the cars does not run dry. this looks good also but has 42mm cap? one above has 45mm
Sealey VS820 Brake and Clutch Bleeding System: Amazon.co.uk: Car & Motorbike
the one linked above sounds great. it has a reservoir so the cars does not run dry. this looks good also but has 42mm cap? one above has 45mm
Sealey VS820 Brake and Clutch Bleeding System: Amazon.co.uk: Car & Motorbike
anyway
So when you have finished ho the hell do you disconnect it? even if you release the pressure in the pump up tank there is still going to be fluid in the pipe or at the very least the reservoir in the car will be full right up to the top of the cap and a little beyond so when you screw off the cap it will go everywhere.
think that's why i gave up with the last one I tried. is there a knack? or am i being thick?
So when you have finished ho the hell do you disconnect it? even if you release the pressure in the pump up tank there is still going to be fluid in the pipe or at the very least the reservoir in the car will be full right up to the top of the cap and a little beyond so when you screw off the cap it will go everywhere.
think that's why i gave up with the last one I tried. is there a knack? or am i being thick?
I tend to use the gunson "dry" for these reasons. You just need to be more careful not to run the reservoir dry.
Another daft thing I did recently was unwittingly pulling the pads out of the calipers while the pressure was connected (god knows how I did it in that order!) Anyhoo I only noticed it had forced the brake pistons out until they clamp directly on the disc when I came back to fit the new pads, that's an interesting one to fix
08-19-2014, 03:48 AM
#19
Thanks for all the responses. I have ordered the sealey vs820 as previously listed. I think the 42mm is a standard European size. I measured and it seems to the right size. Will let you know how I get on.....