Motive Pressure Bleeder Problem

[mdmiller911]

Every time I try to use my new pressure bleeder, fluid comes out from the grommets on the master cylinder. I ordered and installed new grommets but that didn't help. Anyone else have this problem? I've never pumped it over 10psi.

[Bob Kontak]

This link talks about the difficulty of replacing the grommets while the MC is in the car. References to difficulty of seating them properly.

Brake Master Cyl. Problem/Question

Never had to do it myself.

[Zeke]

I don't know what your particular solution is, but you don't need 10 lbs of pressure. In fact, brake bleeding can be done with gravity alone. I'd use a lot less pressure.

[efhughes3]

I've had SpeedBleeders for years now, I can't even remember what my pressure bleeder looks like.

[mdmiller911]

Thanks Bob, I have seen that thread before. It mostly talks about the pre-boosted models. Because my 77 is boosted and the M/C is in the trunk, you can pop these in and out without crawling under the car.

Thanks Milt, I agree. I have read people pressure bleeding at 15psi with a max of 20. I figured 10 would be fine. I cant even bleed at 5psi without it leaking out of the grommet.
It also seems that it is leaking out around the plastic fitting (grommet to fitting seal) not around the master cylinder to grommet seal.

These are new grommets! It seems to me that many people use these pressure bleeders without problems. Any other thoughts? This sounds ridiculous but do the plastic fittings somehow get smaller with age?

[Bob Kontak]

I have two newer VW's and VW chat forums recommend no more than one bar with pressure bleeders.

Motive says not more than 20 as a general rule. Searches in this forum indicate 15-ish.

I bled my 81SC last weekend at 12 psi and found the flow rate of the fluid was much greater with the 911 than the VW's. I believe fluid would have flowed real well at 5 psi and adequately with gravity.

Edit - got it on the boosted vs non-boosted. Sorry.

[Bob Kontak]

Here is a pic of my set up. It looks like the "intake socket" on mine sets a little deeper into the grommet than yours. Not sure if it's anything but you are asking for thoughts.



Regarding replacing the plastic intake sockets - I sure would.

911 355 322 00
911 355 323 00

[Peter Zimmermann]

When I still had my shop we used 12 psi to bleed brakes on all boosted cars. We never had a leak like you describe, but we always replaced the plastic sockets when we replaced the master/cyl, which came with new rubber inserts. Are you sure that your leak isn't the hose? Are your blue hoses new (they look a little ragged on the ends, and should not be clamped), if not check with your local dealer/independent to see if you can buy a few inches of new hose, cut new ones to fit and install using silicon spray. Do not put the clamps back on, and make sure that you use blue hose.

You did remove the overflow tube from the reservoir and put a short piece of plugged hose in its place for the bleeding process, right?

[JP911]

Two ideas:

1. possible that you received the wrong grommets?

2. possible that your brake pedal (or the actuating rod) is depressed, which would prevent brake fluid from passing into the master cylinder...therefore finding it's way out through the grommets?

[mdmiller911]

New hoses, new plastic fittings, new grommets.... problem solved!

Moral of the story: When rebuilding/refurbishing systems on an old car, don't skimp on the little $3.50 parts. Just replace all that little stuff too and save yourself the aggravation. I must have dumped 4 liters of fluid in there just to have it all wasted on the floor. Not to mention the down time waiting for the little parts to ship and the cost to ship!!!

Whatever, I had a good time!

[Bob Kontak]

Sweet!