GMC 7000 V12 clutch failed

[Gmguy]

Hi - I have a 1964 GMC 7000 V12 fire engine and the clutch master or slave cylinder failed - haven’t sorted out which yet. The service manual doesn’t provide any help with identifying a part number.

Does anyone know part numbers for replacements and where to find them? Thanks!

[BobBray]

You may not be able to find new clutch slaves and masters anymore, but if the bores are not bad a brake shop may be able to rebuild them. If the bores are bad, these people may be able to help:

https://whitepost.com/#hometop

[Gmguy]

Thanks Bob - never thought about a brake shop. I’ll check that out.

[LEWISMATKIN]

is this an L7000 steel tilt cab? if it is, it takes the same master cyl. as the DFI series (cracker box cab.) clutch slave cylinders are the same through out the truck line. if the master cylinder is the problem, more than likely, you will have to send it to White Post Restorations, as bob bray suggested. they do superior work. once the repair is completed, i recommend DOT 5 brake fluid (silicone) for the simple fact that DOT5 doesn't absorb water from the air where DOT3 & DOT4 do.

[Gmguy]

Yes, it is a tilt cab. Thanks very much for the info!

[James]

Originally Posted by LEWISMATKIN

is this an L7000 steel tilt cab? if it is, it takes the same master cyl. as the DFI series (cracker box cab.) clutch slave cylinders are the same through out the truck line. if the master cylinder is the problem, more than likely, you will have to send it to White Post Restorations, as bob bray suggested. they do superior work. once the repair is completed, i recommend DOT 5 brake fluid (silicone) for the simple fact that DOT5 doesn't absorb water from the air where DOT3 & DOT4 do.

Normally when you switch to DOT 5 you will need to reseal both the master and slave cylinders with compatible DOT5 seals. The same is true if you went the other way. And don't forget to thoroughly clean out the lines, any traces of the old fluid can cause problems. It is probably best to replace the hose with a new one while your doing it.