450C Clutch Issue

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brentster125
MC crawler
MC crawler
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Joined: Wed Mar 30, 2022 4:31 pm

450C Clutch Issue

Post by brentster125 » Thu Mar 31, 2022 5:53 pm

I recently purchased a 450C project. The dozer runs well and pushes well, but the clutch does not stop the machine. I think something is wrong with the engine clutch because I can only push the clutch pedal about halfway down, but the HLR clutch also appears to be an issue as well because the machine does not stop. I have another 450C and am familiar with the clutch adjustment process. I started tinkering with this one and have found a few issues. The person I bought it from said they parked it for a few years, but it was working fine when it was parked. I'm not so sure...

Issue #1 - I opened up the HLR clutch adjustment plug in the bell housing and noticed that it was screwed down pretty far. I backed off the nut to see if I can reset everything and try to dial it in myself, but the linkage will not spring back up. I'm thinking it is corroded to the shaft. I've tried sticking a hooked tool down in there to grab below it and yank it up, but so far no luck.

Issue #2 - I connected a pressure test gauge to the transmission and I get 0 PSI in any gear, any HLR position, any RPM. The dozer is operational using the HLR lever. I can move it around, spin tracks on heavy load in 1st gear (most of the time), but I did notice it doesn't have much power in reverse. It won't climb a hill, but then other times it will. It doesn't like to move much at idle but will get going once you hit 2000 RPM.

I'm not as concerned with the engine clutch at the moment and would like to at least figure out what is going on with the HLR.

Any ideas would be appreciated. Since I have no pressure on the gauge I'm not sure where to start. Thanks!
Last edited by brentster125 on Thu Mar 31, 2022 7:35 pm, edited 2 times in total.

brentster125
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Joined: Wed Mar 30, 2022 4:31 pm

Re: 450C Clutch Issue

Post by brentster125 » Thu Mar 31, 2022 7:28 pm

Update: After a few days of soaking the HLR linkage in PB Blaster I was able to break it loose with the small pry bar and have it pop back up to the adjustment nut. I did a pressure test with the linkage adjusted up (nut 1/2" from top of threads) and it still says 0 PSI but it does jump up to 50 PSI when I put the clutch in. The dozer wouldn't move at all though.

I ran the HLR adjustment nut back down again and I was able to get the dozer moving. I started playing with the adjustment nut (blind since the gauge always shows 0 PSI) and I was able to find a spot where the dozer will respond when I put the clutch in. When I let the clutch out the engagement is very soft and slow. You also have to run the engine around 2000 RPM to get much movement.

Somehow I need to figure out why the gauge isn't showing any pressure.

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LeonardL
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Re: 450C Clutch Issue

Post by LeonardL » Fri Apr 01, 2022 7:58 am

Check the port where the gauge is threaded into. I have seen those varnish over and be plugged to the point that you won't get a reading on the gauge. Otherwise I'm afraid you have internal issues.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

brentster125
MC crawler
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Joined: Wed Mar 30, 2022 4:31 pm

Re: 450C Clutch Issue

Post by brentster125 » Wed May 18, 2022 11:04 am

It seems that I have internal HLR issues. When I start it cold, the dozer is operational for about 30 minutes. I have to put the RPM's around 2,000 to get it to move when I first start it and it pushes good. Anything under 2,000 RPM and it won't move. Over the 30 minutes I have to continue to increase the RPM's until I'm at wide open throttle and then eventually it's game over and it won't move at all unless I leave it overnight.

From my research it seems that I either have a bad manifold or maybe a bad pump. The pressure gauge still shows 0 psi all the time. How do I determine which one is the issue?

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Dkc923
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Re: 450C Clutch Issue

Post by Dkc923 » Fri Jun 24, 2022 7:09 pm

were you ever able to get to the bottom of this issue and get your pressures corrected?
1974 JD 450C. Old iron is my passion!
12 IH tractors and counting

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