Master cylinder bleeding question

Steve b5 quattro

Registered User
Joined
Apr 11, 2020
Messages
43
Reaction score
6
Points
8
Location
Galway
Hey,so I needed to get calipers replaced last week. The motor factors got me the wrong ones, so I was stuck waiting an extra 10 days for the correct ones to arrive. I plugged up my exposed brake lines best I could. But yesterday I noticed my brake reservoir was empty. I assume il need to bleed the master cylinder.

Any tips/tricks?

TQS

Sent from my SM-G950F using Tapatalk
 
Hey,so I needed to get calipers replaced last week. The motor factors got me the wrong ones, so I was stuck waiting an extra 10 days for the correct ones to arrive. I plugged up my exposed brake lines best I could. But yesterday I noticed my brake reservoir was empty. I assume il need to bleed the master cylinder.

Any tips/tricks?

TQS

Sent from my SM-G950F using Tapatalk
I'm interested to find out about this as I bought myself the one man bleeding system and I was checking the MC from the top and it seems it doesn't have a bleed nipple, at least I didn't find one from the top.
 
Hey,so I needed to get calipers replaced last week. The motor factors got me the wrong ones, so I was stuck waiting an extra 10 days for the correct ones to arrive. I plugged up my exposed brake lines best I could. But yesterday I noticed my brake reservoir was empty. I assume il need to bleed the master cylinder.

Any tips/tricks?

TQS

Sent from my SM-G950F using Tapatalk

Hi! Yes, you’ll need to bleed your brakes. If you have a manual transmission you’ll most likely need to bleed your clutch slave cylinder as well, if fluid in the reservoir has fallen too low.

I have had a time of bleeding with the two person method and finally bought a pressure bleeder (mine is made by Schwaben Tools. If you use that type of pump up pressure bleeder don’t increase the pressure more than 5 psi or the equivalent in bar or the plastic reservoir may explode.

Don’t mix old and new fluid. Watch the fluid at your drain bottle and let it run until it’s clear and without bubbles. I’ve been using Ate DOT 4 brake fluid lately but any DOT 4 fluid is fine, I believe.
 
I have a vacuum bleader and the pressure one,
Oh I was very sure I'd need to bleed the brakes but doesn't the master cylinder need to be blead before I can bleed the brakes?

Is there a way to bleed the master cylinder easily or do i need to remove it?

Yep manual box.

Sent from my SM-G950F using Tapatalk
 
Bleed the brakes at the caliper bleed valve. Brake fluid from the master cylinder reservoir will be drawn through the lines to the bleed valve on the calipers. I hadn't heard of bleeding the master cylinder. That's a new one for me. You should bleed the clutch slave cylinder, though. There is a clutch master cylinder but it is bled when you bleed the slave cylinder. Same system. Just make sure to watch the fluid level in the plastic reservoir so that it doesn't get low and draw in air.

I'm sorry but I don't have experience using a vacuum bleeder but I hear they can be great! I hope it all goes well.
 
And to add... No need to remove the master cylinder.

I should have also mentioned that bleeding the clutch slave cylinder (which also bleeds the clutch master cylinder) isn't as difficult as you would think. If you remove the front left wheel, with the car on jackstands, and look up at an angle to the top of the transmission you can barely see the nipple on the bleed valve or it's rubber cap. Once you reach up there and get your flare nut wrench on it and a drain tube you'll see that it's pretty accessible by feel. I don't think it matters whether you bleed the slave cylinder or the brakes first, as the systems are separate, other than using the same fluid reservoir.

I also sort of remember that it may be easier to bleed the slave cyl by first removing the heat shield above the left axle CV joint at the transmission. Take a look at that at least to see if it might help the access or view of the cylinder.