Hydrovac shaft sealant

[pfarber]

Anyone have any idea whats a good internal thread sealant for the shaft and plate assys?

I am thinking that RTV would be OK.... hydrovacs are dry and normally not exposed to chemicals.

[gerardsrik]

We have made a seal from leather. Our hydrovac leaked braek oil into the vacuum chamber. We made the leather seal and problem solved...
See:

http://home.hetnet.nl/~gerards_j/rembekrachtiger_1.htm

I'am sorry that this is only in Dutch but i think you get a idea of what i mean.

Rik

[Cat Man]

RTV is fine stuff, but don't us it anywere near any sort of an assemby like valves with passages inside. Excess RTV gets into hydraulics or transmission shift valve bodies (or HydroVac parts) and has created real problems plugging passages. We train out technicians not to use it in those applications.

If you feel you need a thread sealant, use a liquid type. Check the "loctite" catalog for the correct product for your internal application. They have many different application specific products that will be better than RTV.

Cat Man

[pfarber]

My hydrovac had sealant on the large nuts that hold the leather seals and plates in the big vacuum cylinder.

SHould anything get oiled before I seal her back up ?

[Hardbird]

I left you a post on G503. I was wondering where you needed thread sealant inside the hydro-vac. This answers the question.

Were the nuts dimpled with a center punch to hold them in place? If not, maybe the sealant was actually some type of thread-locking compound? The nuts on the plate shaft in my hydro-vac had no signs of sealant or thread lock, just dimples.

Hopefully that 1/2 diameter cup seal in your kit was better than mine. I had to but three rebuild kits just to get one good one.

And the fragile paper gaskets for where the vacuum chambers join the the center chamber divider were shrunk and dried out beyond use as well (I did use a conservative amount of Ultra Black in this area to seal these joints in place of the useless gaskets). I tried several methods to give those gaskets new life to no avail.

I mentioned the steps that I had taken for re-assembly in my post as well. My hydro-vac works great, holds vacuum for a long while after the engine is shut down, and has been like this for almost three years now.

Sounds like you are going to have a great truck when you get her done!

Good luck to you,
Ron

[pfarber]

That was me on the G... I've been posting in a lot of differnet MV sites to try and get as much info as I can.

THanks for all your advice.... the Jimmy should be rolling again by next weekend.