65 Kaiser M35A2 project starts

[Gunfreak25]

I believe it’s the hydraulic head. I’ve read the tolerances are so tight that if you hold the quill shaft in your fist for 10 seconds it shouldn’t even fit back into the head. Mine did with almost no hesitation and I clearly remember seeing swirl wear marks on the quill shaft. I will confirm this later by running thicker fuel like waste oil. The thicker fuel raises injection pressure in a worn head masking the problem.

Does anyone have a good used hydraulic head for sale?

 

[cattlerepairman]

@Gunfreak25 When mine had the fluttery exhaust, died randomly and often felt during driving like I had lifted my foot off the throttle (although I was standing on it!) it turned out to be fuel filters. I had discarded that idea, because they were next to new. Changed filters...problem went away.
Good luck with yours and happy to see it moved under its own power!

 

[Gunfreak25]

These filters have less than 1 hour run time on them, it surely can’t be them? My CUCV did all this exactly down to a tee. But only when we took it off-road. We thought it was fuel foaming up and airating. Finally dropped the tank one day and found it rust plugging the sock!
The previous owner told me it ran great for him on the highway. And it’s accumulated so few miles in the few years Will Wagner had it at their museum.

I did find the primary filter top bolt wasn’t tight. The o rings must have settled in. So the booster pump could have been pulling air there.

but yes I agree, feels exactly like my CUCV did which was simply fuel starvation.

 

[Mullaney]

These filters have less than 1 hour run time on them, it surely can’t be them? My CUCV did all this exactly down to a tee. But only when we took it off-road. We thought it was fuel foaming up and airating. Finally dropped the tank one day and found it rust plugging the sock!
The previous owner told me it ran great for him on the highway. And it’s accumulated so few miles in the few years Will Wagner had it at their museum.

I did find the primary filter top bolt wasn’t tight. The o rings must have settled in. So the booster pump could have been pulling air there.

but yes I agree, feels exactly like my CUCV did which was simply fuel starvation.

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Depends on how much crud might have gotten suspended in the fuel and picked up and moved into the filters.

It was really weird on one of my trucks... Cranked it, drove it maybe a mile and parked it. It sat for another week or two.

Went to crank it again and the truck would sputter and cough but no more. When I opened the fuel filters - it looked like I had clay on top of the filter. Whatever it was definitely stopped the fuel flow.

 

[Gunfreak25]

I'll crack the primary open after work and have a peek, thanks Mullaney! I suspect the bottom of this tank could be full of junk too. Just based on how rusty the canisters were when I cleaned everything out. Literally had an inch of muck in all 3 canisters and the filters were so plugged they imploded. I'm going to drain all 30 gallons out, inspect, clean and run the truck at high idle with 5 gals of new fuel and injector cleaner.

I noticed when the truck would die on the road, while letting it sit with the fuel pump still running I could hear a very distinct pitch change in the pump when it regained prime or pressure, that's when it would fire right back up like nothing was wrong.

 

[Mullaney]

I'll crack the primary open after work and have a peek, thanks Mullaney! I suspect the bottom of this tank could be full of junk too. Just based on how rusty the canisters were when I cleaned everything out. Literally had an inch of muck in all 3 canisters and the filters were so plugged they imploded. I'm going to drain all 30 gallons out, inspect, clean and run the truck at high idle with 5 gals of new fuel and injector cleaner.

I noticed when the truck would die on the road, while letting it sit with the fuel pump still running I could hear a very distinct pitch change in the pump when it regained prime or pressure, that's when it would fire right back up like nothing was wrong.

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Definitely sounds like "gunk" of some sort is in there.

I really wish I had the waste water reclamation facility that the company I worked for had. It was really nice to be able to drop a steam wand into the tank and let it run for half an hour. The hot water and pressure would force the gunk out and the waste ended up being claimed without polluting.

 

[Gunfreak25]

Transfer case shifter shaft seal is puking oil (yes vent is clear), enough that my 20 mile journey yesterday sprayed the rear axles a little. So new shifter shaft seals inbound. Oh, and just sitting in my driveway the front left tire went WOOOOOOSH and flat. My fault for using these old, free tubes I was given. 1 step forward 2 steps back wheres the beer?

 

[Gunfreak25]

Primary filter looks great, redid some fuel fittings, good flow after secondary filter, diesel is definitely old but still smells like diesel.

Still no change, struggles to maintain steady rpm under no load in front yard, surges and fluctuates. Out of curiosity I held the pedal near 2000rpm and turned ign off to kill the fuel pump and the rpms actually rose and it surged less!!

Tomorrow’s test is feeding it straight waste oil for fuel to see if the thicker viscosity helps pump pressure in the head. Likewise, will also try new fresh diesel and some cleaner.

 

[Mullaney]

Primary filter looks great, redid some fuel fittings, good flow after secondary filter, diesel is definitely old but still smells like diesel.

Still no change, struggles to maintain steady rpm under no load in front yard, surges and fluctuates. Out of curiosity I held the pedal near 2000rpm and turned ign off to kill the fuel pump and the rpms actually rose and it surged less!!

Tomorrow’s test is feeding it straight waste oil for fuel to see if the thicker viscosity helps pump pressure in the head. Likewise, will also try new fresh diesel and some cleaner.

.
Just fishing... If you turn off the ignition off, the electric fuel pump in the tank stops. Right?

Wonder if a couple of gallons of good clean fuel in a bucket or similar to the in and out ports on the IP - gravity feed - would prove the head is good or that the tank is nasty or maybe lines are clogged?

 

[Gunfreak25]

I did turn the fuel down a few turns because it looks like it was up too high as it came to me ( 8 threads showing, backed it down to 4). It was pretty smoky before but I hadn't driven it really to see if turning it down made any difference. The FDC was bypassed already and I just feel like previous owners forgot to reduce fuel rate. Would too low cause the upper RPM stumble and hesitation issues? Lines are all clear as I replaced all of them stem to stern with nylon.

The fact that it ran great for previous owner and not for me say's its something I did. The fuel shutoff rod was always touchy on this pump, I disassembled and cleaned it thoroughly and tried playing with the torque on the two screws that hold the bridge plate on and found that barely touching the screws would cause the idle to move around and do goofy stuff. So when I get home i'm going to cut the tie wire again, loosen them a little and retie and test. The truck had original safety wire on the two screws that looked professional (military) and if I recall they weren't tight at all.

 

[Gunfreak25]

Thanks to Floridianson for the phone tech advice! Checked fuel pressure at bleeder port and got 30 psi idle…..so far so good…..revved up slowly to 2000rpm, pressure climbed to 40 then 50 and engine started surging like it does at which point fuel pressure dropped to ZERO!! It stayed at zero until the motor was stopped and engine restarted.

So the gremlin is likely the pressure relief valve on the side of the booster pump. It is sticking open and staying open until shutdown and restart. I remember the spring for this valve being weak and the whole assembly damaged from rust.


Should have it fixed soon as I can source some parts.

 

[Gunfreak25]

Here’s the offender….I BELIEVE. The fiber gasket fell apart but it still looked like it was sealing. Hard to figure out what exactly was stuck open here.

 

[Floridianson]

Give me a call when you can. Also with the valve out turn on in tank and see if any crud comes out. Try and place a rag / towel so as to catch and see if there is crud.

 

[Gunfreak25]

I ran the pump and little to no debris came out. Here’s yesterday’s video of the pressure drop. It’s very repeatable. When I shut the truck off it takes about 10 seconds to hear the pitch change in electric pump regain prime. So when the booster valve sticks open I believe it was pushing all the fuel back into the tank, reverse!!

and no it didn’t break the gauge, pressure remained at zero until shutdown and a restart after pump regained prime

 

[Floridianson]

Yea they will run / idle with pressure so low your gage will not pick it up.

 

[Gunfreak25]

So if the fuel is leaking past the check valve the only place for that boost pump pressure to divert to is pushing fuel in reverse back to the tank (fighting against the electric lift pump guess who will win). Which is the reason why on shut down I can hear the electric catch back up and begin priming again. I should be able to verify this by placing a gauge on the booster pump valve. When pressure drops to ZERO at filter heads, the pressure should now be on the inlet side coming from the tank. Crazy but that's my theory. The pressure HAS to go be going somewhere

 

[Floridianson]

Yea we talked about a restriction in the over flow valve or somewhere in the return line going back to the tank. Still believe removing the return line off tank and watch it with in tank running and then with truck running. I know you said you did all the fuel feed and return in Synflex. Is there any way the fittings / inserts are causing a restriction? It should not but crazier thing happen.

 

[Floridianson]

Also the head over flow valve needs to open up some when at high Idle ( almost full rpm ) and that would cause the restriction. Know you said you checked it but any problem with restriction starts with the over flow valve.

 

[Gunfreak25]

I’ll check all of the above tonight and give you a report if it’s not too late there. If you can think of checking anything else let me know! Is there anything in the hydraulic head that could stick and keep pressure at zero?

 

[Floridianson]

If you can think of checking anything else let me know! Is there anything in the hydraulic head that could stick and keep pressure at zero?

Maybe all the folding money you are throwing at the truck. No on anything in the Head to cause restriction.