CAT D4-H Dozer Fuel Issue

[D4Hchase]

Have a D4-H CAt Dozer that I’m having a fuel priming/pressure issue. I completed a full service on the dozer a while back and obviously changed the fuel filter, now, when I crack the line just after the injector pump I can only get fuel out of the first two lines. There is no primer plunger or any other way to prime other than turning the engine over. Any secret to get this dozer primed so I gcan get some work done?

 

[Welder Dave]

Do you see the long hex fitting on the pump on the bottom fuel line? Inside that hex fitting is a screen that can get plugged. Remove the hex fitting and the screen can be removed with an allen key to clean it. Gave me fits on my 931B until I finally released where the screen actually was. Machine would idle fine but rev it up to move and it would rev a bit and then die. Took me over 30 minutes to drive about an 1/8 of a mile back to the shop.

 

[D4Hchase]

Are you talking about the first picture? I see the longer hex fitting on the bottom fuel line that goes to the lift pump. I assume that’s the one your are referencing. I cleaned the other screen filter on the second picture towards the bottom right.

 

[heymccall]

First, are you sure that the square ring in the roof of the separator is intact, as well as the oring on the top nut?
Secondly, when cranking, the fuel must be on, ie...hand lever forward.

 

[D4Hchase]

I know I have the hand lever on, but I haven’t checked the screen that welder Dave is talking about.

 

[D4Hchase]

I know I have the hand lever on, but I haven’t checked the screen that welder Dave is talking about.

 

[Welder Dave]

Yes, the long hex fitting in the 1st pic. It's a pretty fine screen and not much area so it can plug up pretty bad.

 

[D4Hchase]

Checked the screen and orings. Screen was half clogged up. And replaced one of the orings. Didn’t have a helper to crack the line and bleed while I turned the engine over. Maybe will have time this weekend.

 

[Welder Dave]

A mechanic changing a head on mine under warranty said you can loosen the injector lines at the pump to bleed air out.

 

[D4Hchase]

Yeah. That’s how we typically bleed the air is right after the pump, but it doesn’t seem like there is enough fuel being pumped to fully bleed the air. Maybe the screen being clean should help. I assume bleeding at the head would be better since the air is going to go to the highest point anyway, so let the pump get the fuel up high to help clear the air out.

 

[D4Hchase]

Update: finally had time this weekend to mess with the dozer. Bled the lines at the head and after several turns of the key it started right up. At first the dozer would not go into reverse and the right steering was slow but after about 10 minutes everything seemed to be fine. This is after a full trans fluid/filter change and sitting for 2 years. It blew a radiator hose after about 40 minutes, but the hose was dry rotted. Fixed it, now you can only run it for an hour then it will stop moving. I assume this is an overheating torque converter? Any way to diagnose why this would be happening?

 

[Fireman122]

Check your transmission pump pressure. A friend had a very similar issue. Ended up having to change transmission pump. He told me the pump would not build enough pressure and the bypass would stay open and create excess heat.

 

[D4Hchase]

Would this be what you are saying regarding the transmission pump?

 

[Fireman122]

I believe that would be it. He installed it, I was not there. He did say he had to drop a belly pan and take off the floorboards to install. It was not mounted in the transmission.