Hello everyone -- Brand New Member and new to asking questions, however have read and received allot of great information from your site .... Thank You All. Recently a problem surfaced with my 1990 743 BobCat which is how I came across your forum I purchased a 1990 743 Bobcat about 2 years ago. It has approx 2200 hrs of which I put on about 200 of them. The Machine worked great without a hitch and runs & starts great. Last Fall we were changing grades on a buddy's back yard and moving bunch of rock (4 to 6") for a dry creek drainage path. Sudden it began making a grinding noise. We were putting the old girl through paces digging earth & rock. The grinding noise seems to be there whether your moving or not, but does get louder when in moving. Hydraulics all work and machine does move forward and back -- turns both directions, just quite noisy with this grinding noise. Any suggestions what to look at first. Reading past forums I wondered if it could be the Universal Joint coupling engine to main drive pump .... does this rotate at stopped and idle position? Could this be in the main drive chain or ?? Any advice would be welcome
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reaperman
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- Dec 18, 2011
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I second what Jerry says, u-joint. Dont start the machine anymore unless its absolutely necessary, but I would advise not to. You dont want it to do further damage. I had one fail on me once also. Unfortunately, the engine has to be pulled for replacement. To get mine replaced set me back $500, a dealer would have wanted twice that much. I found a local tractor mechanic to do the work. I think parts were approx $125 from bobcat
Thanks for info -- I've got her in shop and on blocks and will check out U-joint. May take a few weeks to find time to pull engine and check it out. I'll let you what I find Thanks Again
Had a little house repairs this winter so took longer to get back to the Bobcat. You fellas got it right ... creeped her into the shop and took engine out with a little help from previous forum threads. It wasn't that bad except for removing the cab due to low head room in shop. The U-Joint was almost completely shot...... probably just enough to drive in the shop. Picking up new U-Jount assembly next week and plan to put her back together...Tx everyone and this forum for all the great advice Couple quick questions before I start putting together. Does anyone have any recommendations to look at or replace anything as precaution measure before the engine goes in? Also is it recommended to replace the Bolts on U-Joint apparently they come separately? Thanks Again
HanSolo
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Assuming it's the same type u-joint as the 843 - plan on getting the attaching bolts from your Bobcat dealer. They're male twelve point 5/32 torx but a 1/4" drive 5/32 socket will get them out. I tried using a caps screw on my 843 u-joint but the profile of the head is too large and doesn't allow the u-joint to flex enough. It's an inexpensive part from Bobcat and there's really no other bolt that will work in those tight quarters. While you have the engine out you might want to thoroughly clean the cooling coils. Mine had thrown a lot of grease and dirt up into the hydraulic coil due to clogged weep hole in fan shroud. You might want to add a few holes in the bottom of the shroud to prevent that.
Well got it back together and didn't go that bad --except the gas shocks that help lift the cab are impossible to compress so we can reattach to the cab? Am I missing something? they were also hard to remove and had to just drive the pins out with hammer / punch. Is there a trick to removing and installing these gas shocks? Attica
[email protected]
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why did you remove them?
OldMachinist
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If you remove the stop blocks the cab rests on when up you should get enough height to install the gas springs.
We removed the cab when pulling the engine to replace the U-Joint.
DUH, should have thought of that. We'll give this a try. Thanks for the tip OM
As OM said, remove the stoppers to get a little more reach. I have had to use screw drivers to lever it into place.
Well, we have it back on the job and it's working great. The gas shocks tips including using screw drivers to leverage them into place worked. We changed oil, alternator belt and all filters (oil, air, fuel, hydraulic) and then cleaned her up and washed her all down ..runs like a new machine All the advice and tips were invaluable, couldn't have done it without all your help..... thanks to everyone and who knows maybe someday I'll be able to offer some advice ... ha ha
