federal girling dual master cylinder rebuild

[koobs90]

I need some help... Attempting to rebuild dual master cylinder. Have the kit from Bean Engineering but cannot disassemble fully. Its is out of the car, tip valve removed, plunger etc. out. The trouble is that I cant get the plastic tank off the rear, and dont want to break it. The piston will not come out of the bore either. It was moving freely in and out but never fully came out and now it is stuck inside the bore. Attempted compressed air without success. My next step is to plug all the ports with correct size plugs and try the compressed air again. Any suggestions appreciated, thank you

[Ceej]

I need some help... Attempting to rebuild dual master cylinder. Have the kit from Bean Engineering but cannot disassemble fully. Its is out of the car, tip valve removed, plunger etc. out. The trouble is that I cant get the plastic tank off the rear, and dont want to break it. The piston will not come out of the bore either. It was moving freely in and out but never fully came out and now it is stuck inside the bore. Attempted compressed air without success. My next step is to plug all the ports with correct size plugs and try the compressed air again. Any suggestions appreciated, thank you

Back in 2019 I was doing the same thing, w/ the same issues. Ultimately I ended up sending it out. As I recall, I used Power Brake Exchange in San Jose, CA.

https://powerbrakestore.com/

Cost was around a hundred fifty or so (in 2019 dollars...), timely and service as promised. I don't know if they still perform this service but IMO they're worth a call. I had no qualms spending the dough. It's the brakes after all.

Cheers!

[h20hamelan]

I have used the Spitfire 1970 or GT6 new from Summit for $70
I could upload a photo if required

I have no clue how water in brake fluid interacts with the alloy master, but on my alloy clutch master I rebuilt, only to find other issues and then with small honing it might have been oversized a bit.

[Uturn]

Recently tried getting siezed pistons out of a clutch MC & SC. Got the piston pushed in with a socket and clamp and then connected a line to a spare Brake MC, added brake fluid and pumped it out after much swearing. Messy but eventually won the day. Repeated this with the front brake calipers to get the pistons out. Will repeat this weekend on the rear brake calipers.

When they are stuck like chuck... compressed air is not going to cut it. I've heard of people using a grease gun to get stuck pistons out, but normally, rapping the cylinder on a piece of wood will eject the piston.

[nmauduit]

I need some help... Attempting to rebuild dual master cylinder.
...
The trouble is that I cant get the plastic tank off the rear, and dont want to break it.
...

As said previously

a strong pull should do the trick ... with a level of risk depending on the brittleness acquired by the reservoir.

https://lotuselan.net/forums/viewtopic.php?f=42&t=51744


good luck !

[koobs90]

I gave up, mc all packed up and going out to Cali, thanks Ceej for the info.

[StressCraxx]

There is a wire retaining clip on the tank nipple that fits inside the master. It can be removed by turning, rocking and twisting the tank back and forth while pulling upward. The clip often rusts in place, so will likely take some penetrating oil.

[2cams70]

I could be wrong but I don’t recall there being a clip to hold the reservoir on the cylinder. If it’s a barb fitting it’s designed to go in but not necessarily to come out. There is normally no need to remove the reservoir from the cylinder. Just remove the two screws at the other end and rotate it for access to the tip valve. This is what it says to do in the workshop manual. The seal around the barb is a non wear item unless you or someone else has done something stupid like contaminate it with mineral oil.

[StressCraxx]

I could be wrong but I don’t recall there being a clip to hold the reservoir on the cylinder. If it’s a barb fitting it’s designed to go in but not necessarily to come out. There is normally no need to remove the reservoir from the cylinder. Just remove the two screws at the other end and rotate it for access to the tip valve. This is what it says to do in the workshop manual. The seal around the barb is a non wear item unless you or someone else has done something stupid like contaminate it with mineral oil.

There is one on my late S3/SS. I have rebuilt it four times in the last 45 years. Not one of Girling's finer designs and they never bothered to put a new clip nor a fresh gasket in the MC rebuild kit.....

[koobs90]

The guys at powerbrake in San Jose were awesome to deal with. I sent them the rebuild kit I purchased, the master cylinder and the proportioning valve and they did both of them for roughly $210 including shipping for the return trip. thought that was a pretty good deal. will reinstall when I get them back but won't be able to review them for sometime as the car wont be back on the road for the next year or 2. Doing a full resto... rear suspension is next and then reinstall the motor, then paint. Thinking of starting a thread with pictures of progress