753 quick/jumpy steering and driving

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Litnng

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Joined
Oct 11, 2009
Messages
14
I just purchased a 753 and the steering is very hard to control. It seems that there is a lot of travel in the levers before any reation comes from the machine, but when it reacts it is quick and hard to handle. There isn't much slow ground speed, it's either not moving at all or it's moving fast. All other functions of the machine seem fine. I looked through many many posts and couldn't find one with this issue. Any and all help will be greatly appreciated.
 

Tazza

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Dec 7, 2004
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16,829
Lift the cab and look at the alloy blocks that connect to the pump. Ensure they are tight. If they are loose, the steering will jump all over. Also, the rubber and steel bushings from the steering linkages to the pump can go bad. There should be no play here. Grab the levers and pull them back and forth, there should be no slack before you feel firmness.
Start with the linkages, ensure they are tight and the bushings are in good shape.
 
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Litnng

Member
Joined
Oct 11, 2009
Messages
14
Lift the cab and look at the alloy blocks that connect to the pump. Ensure they are tight. If they are loose, the steering will jump all over. Also, the rubber and steel bushings from the steering linkages to the pump can go bad. There should be no play here. Grab the levers and pull them back and forth, there should be no slack before you feel firmness.
Start with the linkages, ensure they are tight and the bushings are in good shape.
First of all, thanks for the quick and detailed response. I checked the blocks that fit to the square shafts going into the pump, they look to be made of cast aluminum. Are these the alloy block that I need to be looking at? There is substantial slop there, more on one side than the other, but definately some on both sides. Also, the rubber and steel bushings, are they in the same location as these alloy blocks? Sorry for so many questions but I had to leave the shop and didn't have much time to investigate after your response. Thanks again for all of the help.
 

Tazza

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Staff member
Joined
Dec 7, 2004
Messages
16,829
First of all, thanks for the quick and detailed response. I checked the blocks that fit to the square shafts going into the pump, they look to be made of cast aluminum. Are these the alloy block that I need to be looking at? There is substantial slop there, more on one side than the other, but definately some on both sides. Also, the rubber and steel bushings, are they in the same location as these alloy blocks? Sorry for so many questions but I had to leave the shop and didn't have much time to investigate after your response. Thanks again for all of the help.
Not an issue about the questions!
Yes, those are the alloy blocks i was talking about. They must be tight on the square shafts.
The rubber and steel bushings are pushed into the aloy arm, they are about 1" diameter. There will be one at the alloy arm and one where the steering levers connect to the the long bars that go to the alloy block.
Sorry i can't describe it better, let me know if it still desn't make sense, and i can take a few pictures for you.
 
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Litnng

Member
Joined
Oct 11, 2009
Messages
14
Not an issue about the questions!
Yes, those are the alloy blocks i was talking about. They must be tight on the square shafts.
The rubber and steel bushings are pushed into the aloy arm, they are about 1" diameter. There will be one at the alloy arm and one where the steering levers connect to the the long bars that go to the alloy block.
Sorry i can't describe it better, let me know if it still desn't make sense, and i can take a few pictures for you.
Tazza, No need for the pictures, I have a good idea of what you're talking about now. I'm hoping to get a chance to get to the shop after work tomorrow to do some more investigating. Do you feel that this could be the whole cause of the problem that I'm having or could a damaged pump or other issue cause these symptoms too? Thanks again.
 

Tazza

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Dec 7, 2004
Messages
16,829
Tazza, No need for the pictures, I have a good idea of what you're talking about now. I'm hoping to get a chance to get to the shop after work tomorrow to do some more investigating. Do you feel that this could be the whole cause of the problem that I'm having or could a damaged pump or other issue cause these symptoms too? Thanks again.
I'd suspect its your problem. I don't think any pump "fault" could cause this problem. Its usually wear/slopyness in the controls. It doesn't take much of a turn on the pintle shaft on the pump to cause it to jerk around.
If you had a pump problem, you generally have low drive power, noise, not jerkyness.
The other thing *may* be your shock absorbers, but i'd look at linkages first.
 
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Litnng

Member
Joined
Oct 11, 2009
Messages
14
I'd suspect its your problem. I don't think any pump "fault" could cause this problem. Its usually wear/slopyness in the controls. It doesn't take much of a turn on the pintle shaft on the pump to cause it to jerk around.
If you had a pump problem, you generally have low drive power, noise, not jerkyness.
The other thing *may* be your shock absorbers, but i'd look at linkages first.
Sorry for the delay in response. I have had time to tear into my machine now and there is a lot of slop in both pintle arms and all 4 of the bushings are shot. I will be replacing all of these parts. I have the engine pulled out and will be painting the whole machine, so it will be a little while before I'm sure that all of the problem with the steering is in these parts. I will post more once I get reassembled. Thanks again for the help.
 

Fishfiles

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Joined
Feb 8, 2007
Messages
1,698
Sorry for the delay in response. I have had time to tear into my machine now and there is a lot of slop in both pintle arms and all 4 of the bushings are shot. I will be replacing all of these parts. I have the engine pulled out and will be painting the whole machine, so it will be a little while before I'm sure that all of the problem with the steering is in these parts. I will post more once I get reassembled. Thanks again for the help.
Those alum. pintle arm blocks that where mentioned come in two sizes , the square shaft coming out the Sunstrand is approximately either 5/8 or 3/4 , the serial number usually is not enough to get it right all the time , and the tag number off the pump is needed , I find it's best to measure the shaft before ordering to save time ------------in the field without parts there is a shade tree mechanic fix for looseness , cut a strip of the end of a worm drive hose clamp and jam it in to take up some slack --------------locktite is a must when reassembling , a big mistake I see a lot of people do with locktite is to not clean the bolt and the threads of the block to get rid of the grease , it don't work too good if you don't -----------I have a bent wrench to tighten the arm on the left side if sitting in the seat which is pretty hard to do without removing the top spring plate , also grind a little meat off the box end of the wrench as head clearance is rough , put a pry bar under the arm to hold it up while trying to tighten the bolt , I also cut the open end off the wrench and use a deep dish socket and extention as a cheater pipe , those round cam rollers can be rotated to get the flat spots out the way instead of replacing -----------------a few thoughts that may help someone else ------fishfiles
 

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