Master Cylinder Feeder Lines

grizzly · 12-16-2003, 05:03 AM

Hi,

I am in the process of rebuilding the pedal cluster, new throttle and clutch cables and new master cylinder on a 73 911E. Everything has gone relatively smooth until I tried to get the MC feeder lines to seat. I removed the reservoir to get more play in the lines but I still can't get enough leverage to get them to seat properly. I saw a thread about bending a flathead screwdriver to use as a tool to force the grommets in but I had no luck.

Any ideas/tricks?

Thanks,

Brian

IROC · IROC's Garage

This is a tough one. What I did was to get the master cylinder roughly in place and then get the lines seated as well as possible then I used a pair of Vise Grips to grab the lines and then squeezed the Vice Grips and the master cylinder together effectively pulling the lines down into the master cylinder.

Honestly, this was one of the most frustrating things I've ever done on my car...

Mike

grizzly · 12-16-2003, 05:27 AM

Mike,

I was thinking the same thing but I was worried that I would kink or crush the hard lines. When you used the vice grips, did the lines feel like they were close to failing?

I agree, this is definitely working its way to the top of the PIA jobs.

Thanks

IROC · IROC's Garage

It's been years since I did this job, but if I remember right, the lines seemed pretty sturdy. I tried to grab them above the area where the little "trumpets" seat in the master cylinder grommets so that any scratches, etc., would only be cosmetic and would not affect the sealing of the lines in the grommets.

I hated that job. :>)

Mike

Neilk · 12-16-2003, 05:51 AM

I agree it's a lousy job. IIRC, I pulled the pedal cluster so that the bolts that MC attach to would be out of the way. Then I wiggled the MC pretty firmly while pushing the lines into it. After 5 minutes of wiggling both lines were in. The lines are pretty strong so don't worry about bending them.

BTW, this was after an hour of trying more gentle methods.

Early_S_Man · 12-16-2003, 06:53 AM

To get the grommets to seat easily ... it helps to immerse in boiling water for a couple of minutes, then remove and dry with paper towels. Be sure that the wells in the master cylinder are coated with Dow Corning 4, 111, or 112 Silicone Grease before attempting to seat the grommets!

When installing the hard lines, make sure that the grommet has silicone grease applied inside the seating area ... Q-tip works well for application of the grease.

analogmike · analogmike's Garage

I just did this on my 73 and it was a MAJOR HASSLE until I figured out the easy way.

Just put the grommet on the master cylinder feed line, then coat it with a bit of brake fluid. Then you can easily squeeze it into the master cylinder and know that the line is seated at the bottom.

I have a hard brass flared line and there was no way to get it seated with the grommet in the M/C.

Another interesting thing I learned was that gravity brake bleeding works pretty well. I jacked up the front of the car with jack stands on the highest setting on the front torsion bar tubes. Then when I filled the brake fluid tank, I could see bubbles coming out of the M/C (I use ATE blue so easy to see). My manipulating the brake pedal I could get the bubbles coming out well, hold the brake pedal about halfway down and pulse it. After a while the brake started getting firm, certainly safe for street driving. I bled one front brake and got just a few small air bubbles. Will bleed the rest tonight. It's a good idea to use a pressure bleeder to check the sealing of the hoses on top of the M/C.

Hope that helps!

911pcars · 08-19-2008, 10:03 AM

Everyone. Join Mike and the gravity bleeding group.

Using other bleeding methods (pressure, vacuum and manual pumping) , I estimate a huge amount of new brake fluid is wasted. Save our planet - gravity bleed.

Sherwood

analogmike · analogmike's Garage

I pressure bled the other 3 brakes tonight. I put about a quart of ATE blue through to get new fluid in the calipers for racing. The front had a tiny air bubble that came out in one second. The rears had NO BUBBLES, the gravity bleeding after changing the M/C had worked fine.

My new M/C and rebuilt calipers feel great now, and while I was in there I replaced the clutch cable and cleaned up and repainted the pedal cluster and floor area.