Early 8n Hydraulics

[JRinElginTX]

Hello all! Working on the hydraulics now and have run into a wall again. The lift fails to lift at all, upon inspection the pump would bubble from the top, I didn't notice any fluid leaking from the top of the cover down into the sump. Seems like a pump issue so I'm in the process of rebuilding the pump, all of the valves show dark/black scoring marks. I plan on replacing the gaskets and valves since I've come this far and the rings on the piston in the cover. I am having an issue removing the valve body from the side of the pump. I've removed all 4 bolts, but it seems to be seized to the unit. I have used a putty knife and rubber mallet to break it loose, but no luck. I've included a few pictures, but can't help to think I'm missing something. I've been using the FO4 manual this far. Thanks again!!

 

[JMOR]

(quoted from post at 21:57:05 05/20/14) Hello all! Working on the hydraulics now and have run into a wall again. The lift fails to lift at all, upon inspection the pump would bubble from the top, I didn't notice any fluid leaking from the top of the cover down into the sump. Seems like a pump issue so I'm in the process of rebuilding the pump, all of the valves show dark/black scoring marks. I plan on replacing the gaskets and valves since I've come this far and the rings on the piston in the cover. I am having an issue removing the valve body from the side of the pump. I've removed all 4 bolts, but it seems to be seized to the unit. I have used a putty knife and rubber mallet to break it loose, but no luck. I've included a few pictures, but can't help to think I'm missing something. I've been using the FO4 manual this far. Thanks again!!

ust gasket-stuck.......beat it like a screen door in a tornado!

 

[carlntexas]

Those chambers are stuck on good on my pump. I used a putty knife and hammer to break them loose then came the hard part getting all that glued on gasket off.I used a $100 kit I got on Ebay and my pump works like new.

 

[JRinElginTX]

Thanks guys!! I was thinking about using mineral spirits to clean it out. Still have some left from removing the cosomline from my Mosin. Sound like that will work?

 

[ZANE]

I seriously doubt that the pump was what was causing a no lift sympton??? If there were no broken springs in the side chambers, my advise would be to put the chamber valves back in where each one came out and put the bolts back in and the caps etc and start over. I would think it was a linkage problem or a stuck control vavle etc or even the PTO not engaged and not that pump. Don't go putting new valves in the side chambers either unless you have the tools to re-cut the seats. The old ones are worn in to fit and the new ones won't.

Zane

 

[kylemorley]

Just curious - did you ever do a system pressure test before or after
the overhaul?

 

[Dan]

Another warning - those gaskets have asbestos in them - getting them scraped off is VERY hard but take care to wear a proper mask. Also - the new gaskets are a bit thinner than the originals - the only solution I found was to stack two aftermarket Tisco gaskets, or use one slightly thinner New Holland gasket.

 

[JRinElginTX]

The springs look good on one side, I'm going to inspect the other side and if they look good I'll leave them as is. I don't have a cutting or reseating tool. I figured the replacement parts were correctly sized and ready to go. I will order a new control valve however if I can simply install it without a special tool. The lift worked originally, but never went up all the way and wasn't reliable to work when I needed it. Now it has just stopped lifting up all together. I checked the special metal pin on the cover that is designed to wear out, but it is in great shape. All I could see in the inspection hole was the pump bubbling directly over the pump itself. There was also alot of crud in the bottom of the pump. I'll keep ya'll posted!

 

[kylemorley]

May be worth mentioning here that the chamber gaskets set the
width of the assembled pump where it fits over the PTO support,
so if the gaskets are too thin the pump won't fit over the PTO
support, and won't fit into place, which is very puzzling and
irritating if you don't know what is going on.

I just did a pump using the manilla-colored gaskets nnalert is
selling now. They were a bit thinner than the old (probably
original) ones and made the pump a tight but doable fit to get
back in - I had to tap the pump into place with a rawhide mallet.
Correct thickness gaskets would make the job much easier.