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MG TD TF 1500 - Lockheed master cylinder rebuild

Hello, This is the end of the piston in my Lockheed master cylinder. It appears the previous owner mfg a bushing to get a tighter fit on the push rod, but as this is the first and only Lockheed piston I have seen I am not sure.
Any thoughts would be greatly appreciated.

Regards, Tom


tm peterson

The service manual makes no mention of this thin shim washer. I will check my parts manual at home.
Any input for this would also be welcome

Regards, Tom


tm peterson

The thin washer is now sorted out, but I am still curious about what looks to be an insert made by the previous owner.

Regards, Tom





tm peterson

Tom,
I would replace the master cylinder and not take any chances in case of a bodge by a previous owner.
They are not that expensive and you have peace of mind.
Regards
Declan
Declan Burns

Hi Tom
I have a bin of master cylinder parts and complete used units of you need a part.

Gary
gl krukoski

Gary and Declan, thank you. The main casting is in fine shape, it is just the piston that appears a bit doggie. From the Frame Up sells an improved piston.. center ribs to hold alignment in the cylinder. I will check that out.
Regards, Tom
tm peterson

Gary, I am at n86mk at aol dot com

Second digit is actually the numbers two.

Regards, Tom
tm peterson

Hi Tom
Give me a call 763------226------5789

Gary
gl krukoski

Tom
When rebuilding the original Lockheed MC’s you have to be careful. There were three updates made during TD/TF production regarding the internal bypass valving. Changes were made to the piston and whether the wave washer was used.

The shim in the front of the piston is a bodge repair. Likely either the original push was shorten too much and had excessive free play or(?). Hard to second guess what people have done over the last 70 plus years. Note that when the MC is bolted in place it is necessary that there be a tiny bit of free play /air gap between the push rod and the piston. If not then the MC reservoir reservoir hole is partially or totally obscured at rest and will not allow applied fluid to return to the MC in a timely manner. After several applications of the peddle the brakes will drag and eventually lock up. This either necessitatesa long wait for the fluid pressure to be relieved or a ride of shame to get home and hunt down the issue.

Mismatched internals that prevent the internal pressure release valve to work as intended also will create the same issue.

If unsure the rebuild kit is the correct one for the particular MC in use I would simply purchase a modern “Lockheed “replacement. If buying a kit for the LockHeed try to find a kit that replaces all internals including the piston to insure matched components. The TRW MC would be my next choice but stay away from the Chinese knockoffs.

Bill Chasser
TD-4834
TD/c-8151
W A Chasser

Replacement part heasing Tom's way.


gl krukoski

Many thanks to Gary and Bill.

Regards, Tom
tm peterson

This thread was discussed between 29/07/2025 and 08/08/2025

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.