Hydraulic head

[mechanix]

Does the nut in the middle of the HH have a seal under it or is it just a machined fit? Looks like mine has started to leak.

 

[Seth_O]

Are you talking the one on the top of the head, or the one on the side? For the nut on the top of the head mine did not have anything underneath it, although I have seen posts from folks I respect who have said it should have a copper washer underneath.

The one on the side (actually the fuel delivery valve screw) is a fairly common leak (mine did) and there is no washer underneath it, just a spring.

 

[hdexpert]

I've spent a lot of time recently working on HH and none of them had a washer under the center top bolt. Take your bolt out and see if there is a burr on either surface. If so, try to sand it smooth. If not, you might try a copper washer. Just make sure it's thin so you're not changing internal pressures in the HH.

Oh, and

 

[Floridianson]

sometimes what look like bolt is realy where number three fuel line has split in head. Use air blow off fuel and watch while running.

 

[mechanix]

Yep the bolt in the center. The plug on the side is dry. Cleaned it off and ran it. Its not coming from the lines. It starts seeping out from under the cylinder ID plate on top of the head. I noticed it yesterday after I picked up my trailer. Had fuel blown back onto the step under the drivers door. On the backside of the inner wheel well. Hadnt done it before. I was kinda flogging the truck bringing it back. Never got over 1050 on exhaust temp though. I will have to check it out this weekend.

 

[Floridianson]

Yep the bolt in the center. The plug on the side is dry. Cleaned it off and ran it. Its not coming from the lines. It starts seeping out from under the cylinder ID plate on top of the head. I noticed it yesterday after I picked up my trailer. Had fuel blown back onto the step under the drivers door. On the backside of the inner wheel well. Hadnt done it before. I was kinda flogging the truck bringing it back. Never got over 1050 on exhaust temp though. I will have to check it out this weekend.

I like removing the ID plate then checking where the leak is. I just take tin snips but you say it's the bolt then its the bolt