550G steering problems

[550Gary]

First, I would like to thank Heavy Equipment Forums.com for their site.

Second, Model 550G Dozer, serial # 7544458..(last six digits), Pedal Steer

Third, I highly recommend the TM140401 manual (complete) for any repairs. Mine copy is wore thin by all the use it has seen. However, it does not lay out the overall view of each component and their operation.

A little history: started having steering problems around 1 year ago.. My right side track had completely failed while traversing a hill. How I got up the hill to level ground is another story. After removing the back cover, the pressure hose to the Piston housing had broken off. The special shoulder bolt also on the Piston housing had been eaten down to a nub and the area (hole) it went in on the steering clutch was messed up. Both were repaired and reused.

I replaced the hose and fittings and thought it had fixed the problem….I did not dig any deeper into the steering clutch as I was unfamiliar (even after 30 years) with its internal workings. Even today, after much study and searching, I am not certain as to how it works.

From that time on, I had problems with the steering on the right side, not allowing the left side to move while holding down the right pedal. However, this too was intermittent allowing me to continue my daily task. Then one day, luckily while I was at home, the dozer got stuck in a place where it should not have, all accounting to the right side tracks failing to move when depressing the left pedal. While the right side pedal allowed the left track to move, it simply dug me deeper in the hole..,another story on getting it out.

Observations and repairs:

While holding the right pedal down, the left track will move with no problems….While holding down the left pedal, the right side will sometimes move but most of the time will not move.

I checked the pressure of the control value and got a reading of around 60-90 psi the left side and 140 psi for the right side… removing this valve, I inspected the spools and determined that either one or both of the housing and spools needed replacing due to thirty years of wear. Finding such parts are like pulling hen’s teeth. I did find a 450G pedal steer housing with spools. The spools were what appeared to be from a later serial number than my machine. I replaced the housing and checked the newer spools for PSI. What I got was a lower pressure as the spools were completely different that the originals….Since the housing was the same for all, I place the original spools into the housing with the following results. The right side had around 150 and slowly increased to 170psI. (180psi +/- 15psi). The left side increase a little to 120 psi. Yet this is not enough pressure to release the brakes on the right side when I depress the left pedal...I was back to square one...I then removed the rear cover and transmission (easy on the 550G) and found the hoses intact. However, the anchors on top of both brakes had moved from the center line of the steering drum.This no doubt contributes to the problems I am having but I do not understand how this brake system works with two phases (brake clutches within the drum itself and a brake belt around the outside of the drum that appears to be nothing but manual when ever a pedal is depress.) I have not check either of the drums for leakage nor have I removed them from the trans housing just in case I needed to revisit, trying to understand just what they are doing when I depress the pedal..I think this is paramount to fixing the problem.

I hope someone can understand this post and have some information that will lead tot he permnament repair of the problem. Thank you in advance.

550Gary
p.s. I do have pics of each steering clutch if needed.

 

[mg2361]

I highly recommend putting all the original valves/housing back on the machine. There are different valves for pedal steer, lever steer with torque converter and pedal steer, lever steer with direct drive. So 4 different valve configurations. Then perform all the necessary brake pedal and brake valve adjustments as outlined in the Operation and Test manual TM1403.

 

[550Gary]

The housing for the control valve appears to be newer but is the same housing #eve if a new one could be purchased? Do You still recommend I change the housing back to the original? I guess another question I had is which one (the spools or the housing) is harder, thus which one would wear out the fastest?..

 

[550Gary]

since i have not disturbed the interior rod to the anchor and the manual recommends no adjustment would be necessary if not disturbed, I have not done any internal adjustments..

The adjustments on the control valve other than stops(2 per pedal) would be the .80 inch the pedal is to move before the pressure drops to zero....This I have done with the original spools and newer housing.

Also, I checked the hose running from the trans control to the steering Brake control valve and it is ok.....also remove this hose from the trans control and checked the pressure there just in case the low pressure was originating from there. It stay at a 180 Psi constantly.

I also as you suggested some time ago to another, blocked off the filter relief valve. It also had an increasing the pressure affect that I posted.

as your suggest, I will need to replace the trany back, seal it all up and start over. Is there anything I can check on the steering clutches and anchors, etc. before I put them to spec and close up the system again?.


550Gary

 

[mg2361]

Edit: Valve housings are all the same according to the parts page. The spools are all different.

I had problems with the steering on the right side, not allowing the left side to move while holding down the right pedal.

Classic adjustment issue.

With that being said, if this machine came into me knowing that the customer had been in there, I would first check steering clutch pressures (both at the same time) to see what I have to each side. What did you have specifically in neutral at idle and at 1500 rpm? Then I would perform all external adjustments to the letter. If you disturbed any internal adjustments, then they have to be checked and adjusted to spec.

Since you have the rear cover off, I would probably recommend removal of the steering clutches for inspection, and at a minimum, a resealing. Piston housings on them have been known to crack. Plus the driveshaft between the clutch and the differential like to break, so I would want to inspect them for cracks.

 

[550Gary]

Edit: Valve housings are all the same according to the parts page. The spools are all different.



Classic adjustment issue.

With that being said, if this machine came into me knowing that the customer had been in there, I would first check steering clutch pressures (both at the same time) to see what I have to each side. What did you have specifically in neutral at idle and at 1500 rpm? Then I would perform all external adjustments to the letter. If you disturbed any internal adjustments, then they have to be checked and adjusted to spec.

Since you have the rear cover off, I would probably recommend removal of the steering clutches for inspection, and at a minimum, a resealing. Piston housings on them have been known to crack. Plus the driveshaft between the clutch and the differential like to break, so I would want to inspect them for cracks.

********
The original steering clutch pressures (both at the same time) were: the left side at 60 psi and the right side at 100 psi. The correct psi for this machine is 180 +/- 15.

I had already performed a re-alignment of the linkages minus the internal linkages. They have never been moved in thirty years of use. I did find a clutch valve housing with the same T# for this machine...It seems the 450 G and the 550G have the same housing. The spools for this housing were different from my originals and as you suggest, I did not know if they were from a pedal/Torque converter unit or a pedal/direct drive unit....The pressure with these were too low with the left being 90 psi and the right being 120........I replaced both spools with my originals and the left became 120 PSI and the right went up to 150psi...While using the right side continued to climb to around 165-170 psi while the left side of the steering valve, the one with the major problem would intermittently/slowly jump up to 150 but then would disappear as rapidly as it showed up....Being at idle or 1500 PRM makes little difference in the pressure to both...The pressure of the hose from the trans control valve to the steering clutch valve remains at 180psi at all speeds....Did not check it while in gear,neither forward or reverse.

Question; while I have the trans out and the steering clutch brakes exposed, if I place pressure on either of the steering clutch brakes directly/individually, (as used in the transmission testing for leaks) should the pressure stay up without moving for a specific amount of time? I ask this questions as I do not have the TM 1403 Operation and Testing manual and do not know what is in it or even if it will help with this problem.

while I have some pics that show the H frame may be a little over the top on the right side steering clutch Brake unit, would this affect the pressure here. as I can see no reason other than leaks that would make the pressure lower than required?


I do again thank you for your help

earthmover

 

[mg2361]

TM 1403 Operation and Testing

This manual (TM1403) has all the diagnostic and adjustment procedures for the machine (a different manual is used for the engine). It also has all the electrical, hydraulic, and powertrain schematics. This manual is a must if you are doing your own troubleshooting and repair work.

The adjustments in the repair manual TM1404 are basic adjustments. TM1403 has adjustments that require a pressure gauge and gets into much more detail.

 

[mg2361]

The pressure of the hose from the trans control valve to the steering clutch valve remains at 180psi at all speeds

Tells me there is either a misadjusted spool, or excessive leakage. I would be going for adjustment first.

if I place pressure on either of the steering clutch brakes directly/individually, (as used in the transmission testing for leaks) should the pressure stay up

Probably not. The clutch manifold has steel seal rings and they do not provide a perfect seal. You could still pressurize the clutch to 180 psi to see if there is leakage elsewhere.

 

[550Gary]

will have a copy of TM 1403 by Sat. Have the whole set of TM 140401-22. They have served me well but I have only recently run into a problem where hydrolic pressures and such need to be used....All the rest is mostly back and white in the need to repair or replace....

 

[550Gary]

Tells me there is either a misadjusted spool, or excessive leakage. I would be going for adjustment first.



Probably not. The clutch manifold has steel seal rings and they do not provide a perfect seal. You could still pressurize the clutch to 180 psi to see if there is leakage elsewhere.

there according to schematics, four sealing rings...two of which are Steel (washers) and another two, probably o-rings either next to or on the Clutch Pressure Manifold. Beside from cracks in the piston, would it be suspect to any leakage...

Am going to do a complete overhaul of each steering clutch brake along with all the hose connections, etc. after I pressurize them.

Do you have any ideas of testing these. use of air is out, my air is only 150 psi...I think pressuring using hydraulic fluid outside is also out?

thanks for the advice.

Earthmover

 

[mg2361]

There is no procedure from Deere on pressure testing the steering clutches outside of the machine. So you are on your own there. The only published method for testing steering clutch leakage is to monitor the cooler pressure. That procedure is in the manual you ordered.

 

[550Gary]

There is no procedure from Deere on pressure testing the steering clutches outside of the machine. So you are on your own there. The only published method for testing steering clutch leakage is to monitor the cooler pressure. That procedure is in the manual you ordered.

are you speaking of the 2nd line to the steering clutches?...If so, my machine has no 2nd. line but rather only one line that comes from the steering valve above it.

 

[mg2361]

are you speaking of the 2nd line to the steering clutches?

No. There is a specific procedure for checking leakages in both the steering and transmission clutches. It has nothing to do with the lines that go to the steering clutches.

 

[550Gary]

No. There is a specific procedure for checking leakages in both the steering and transmission clutches. It has nothing to do with the lines that go to the steering clutches.

Ok...I just knew that a "cooler line" had been added later models on the steering clutch brake unit.

I did find out I was under a wrong assumption about the control valve. Pressure is going To the steering clutch brake unit, releasing the clutch plates thus allowing travel through the trany gears. Once a brake pedal is pressed, this pressure is dumped into the trans housing thus reducing the pressure to zero. At the Same time, the brake band on the steering clutch brake unit stops that side of the machine from moving. This Allows the other side to continue to turn, thus changing the direction of the machine.

Now have a ability to test each component, clutch valve with spools, steering clutch brake, etc outside the machine. Maybe I can Find out where that pressure offs going for as you suggested I have adjusted these accordingly to the numbers in the manual I do Have with no success.

Thanks again

Gary

 

[mg2361]

I have adjusted these accordingly to the numbers in the manual I do Have with no success

According to the TM1403 manual? You need to adjust them according to the 1403 manual and not the TM1404 manual.

 

[550Gary]

According to the TM1403 manual? You need to adjust them according to the 1403 manual and not the TM1404 manual.

just got the 1403 manual in today...from what I have read so far, i can still perform the air test on the trans. and rebuild both of the steering clutches. I will make sure the linkages to these are within tm1403/1404 specs before reinstalling the trans and filling it with hydrolic fluid. as per your recommendation, I plan to recheck the pressures from above and adjust to specs accordingly. being thirty years old, the old girl deserves a refit.

thanks for your help. will post it all comes out. thanks again

550Gary

 

[550Gary]

having problems with realignment of steering brake...It wants to wobble which appears to be part of the problem in the first place. The brake band had moved on the steering clutch while at the same time, the Clutch was also off track.to one side (the outer side)

Today, the reinstall of the steering clutch and housing is loose when the final drive bearing is put into place....keep in mind that the trans is still out and the steering shafts on either of the steering brake/ housings . The special cap screw keep wing the inner part of the steering brake from moving will not remain tight against the housing...I think the inner steering shaft will provide some support but not sure..I understand it is an adjustment problem but not sure where to start...

Any help out there will be appreciated.

Thanks

550Gary

 

[mg2361]

The are a little loosie goosy until all shafts are installed.

You said you touched no internal adjustments, correct?

Post a picture of the installed clutch. Also post a picture of the anchor above the clutch.

 

[550Gary]

The are a little loosie goosy until all shafts are installed.

You said you touched no internal adjustments, correct?

Post a picture of the installed clutch. Also post a picture of the anchor above the clutch.

thanks
I have not touched them yet. today, I am going to check these parameters. Hopefully they have not moved. However, they should change a little with wear and tear (use) of the break band.

Yes it seems when I placed the final gears into the left side steering brake,it tightened it up. Finally got the trigger set the way it suppose to be?

Will get some pics today..doing a little at a time...making sure of what I am doing. at my age I have to force myself to recheck all.

Thanks again for your help.

550Gary

 

[550Gary]

here are a few pics....am having a problem adjusting the internal steering Brake rod. Am running out of adjustment on rod from 'over center brake lever' to 'quad lever'.
used the 7.69mm adjustment(no chisel mark here) have pics of this next post..can only post 4 at a time.