Hydraulic Head Plunger Bore Screw Leak

[randygk]

Our '67 Kaiser M35A2 with the Hercules runs good but is leaking fuel at the center screw between the injector lines on top of the hydraulic head. I see they call it a Plunger Bore Screw. I pulled the screw and did not see any seal. Is there supposed to be a seal here? I looked at several TM's and did not see any seal listed.
Thanks

 

[welldigger]

No seal is supposed to be there. It's a machined fit individual to that screw and that head.

I have heard of people putting an o ring or copper crush washer under it to stop the leaking. I don't know how effective that would be.

 

[brianp454]

Can you post a couple pics of the leak and screw?

 

[randygk]

Picture of the Plunger Bore Screw



I can give you a picture of the screw but I will not recreate the leak. Evidently removing the screw and re-installing it stopped the leak. It wasn't very tight (but wouldn't call it lose) when I removed it, so maybe cleaning it and re-tightening it was all that was needed. Will have to drive under load, but seems ok at idle.

 

[m-35tom]

load or not makes no differance

 

[randygk]

Got engine up to temp and full throttle - no leak

 

[mechanix]

Mine did the same thing. Loosened and tightened it and it has been fine since. Mine started after I turned up the fuel a little bit. It was fine before.

 

[TsgtB]

This is an old post, but my center plunger screw must be torqued down to over 100ft lbs...
I sprayed it with PB and hope it comes loose next try....

 

[m-35tom]

why do you want to remove it?

 

[TsgtB]

why do you want to remove it?

I'm having "no fuel issues"... had no fuel at the filters, wouldnt even dribble with the primary off (in tank pump was humming but not pumping). So i put the parker pump in, had good spray on primary drain and no bubbles at the secondaries (let it run good). But no start, cracked the injector lines and all is dry.
So i mentally prepped for pulling HH, (have one off donor engine). This is a depot rebuild with about 50 miles on it.
I wanted to pull the center HH plug and put a dowel in it to see if it moves or if its stuck.
NOW someone said it could be the boost pump... so, i'm at a loss.
Havent totally torn into it yet, searching for all the answers i can get.

 

[welldigger]

I'm having "no fuel issues"... had no fuel at the filters, wouldnt even dribble with the primary off (in tank pump was humming but not pumping). So i put the parker pump in, had good spray on primary drain and no bubbles at the secondaries (let it run good). But no start, cracked the injector lines and all is dry.
So i mentally prepped for pulling HH, (have one off donor engine). This is a depot rebuild with about 50 miles on it.
I wanted to pull the center HH plug and put a dowel in it to see if it moves or if its stuck.
NOW someone said it could be the boost pump... so, i'm at a loss.
Havent totally torn into it yet, searching for all the answers i can get.

Just go ahead and pull the hh. It's not that big of a deal. Chances are the button came off. Which is an irritating and common problem.

It's comparatively rare for a booster pump to go bad.

 

[TsgtB]

Thanks guys, not sure if i've been cross posting (maybe a little) for the same problem, but for different possible fixes...