Power steering moan

Have you made changes to your coach? Improvements? Remodel? New technology? Tell the story and show some pictures here.
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rustyrobins
Posts: 19
Joined: Tue Oct 19, 2021 9:27 am

Power steering moan

Post by rustyrobins »

Hi Guys,
This is not a new subject but I am still needing help. I have typical Sheppard M80 gearbox with hydro-boost brakes and a Vickers vane pump on a Cat 3126 engine. My steering moans really loud when I make turns at slow speeds especially when using the brakes. We are in the Seattle area. Getting help has been difficult. I have called about 30 shops and truck repair. I tried Gitt Springs in Auburn but they kindly didn't want to get too involved. I don't know if I can drop the steering box myself seeing how it is incased in a large steel box with pitman arm the location it is. The guy at Gitt Springs tried bleeding it at the gearbox but it only helped for a short time. I have read here on the forum how people have gotten help in other parts of the country with their steering. My steering is not leaking and ATF looks ok. The moan can't be normal and seems it may be getting worst. I compensate by trying to corner with foot off brake and RPMs up a bit. We hope to travel a bunch this year and next year. Anything information at all may start me to resolve this. Thanks everyone. I have done a lot of work to the motorhome in the last 18 months of which most of the information I got here. Thanks Again
Rusty
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: Power steering moan

Post by ProCycle »

Call Redhead Steering Gear. They are the experts. They are right down the street from Gitt Springs in Auburn.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
TDJohn
Posts: 570
Joined: Sun Oct 27, 2019 11:34 pm

Re: Power steering moan

Post by TDJohn »

rustyrobins wrote: Wed Jun 01, 2022 11:12 pm Hi Guys,
This is not a new subject but I am still needing help. I have typical Sheppard M80 gearbox with hydro-boost brakes and a Vickers vane pump on a Cat 3126 engine. My steering moans really loud when I make turns at slow speeds especially when using the brakes. We are in the Seattle area. Getting help has been difficult. I have called about 30 shops and truck repair. I tried Gitt Springs in Auburn but they kindly didn't want to get too involved. I don't know if I can drop the steering box myself seeing how it is incased in a large steel box with pitman arm the location it is. The guy at Gitt Springs tried bleeding it at the gearbox but it only helped for a short time. I have read here on the forum how people have gotten help in other parts of the country with their steering. My steering is not leaking and ATF looks ok. The moan can't be normal and seems it may be getting worst. I compensate by trying to corner with foot off brake and RPMs up a bit. We hope to travel a bunch this year and next year. Anything information at all may start me to resolve this. Thanks everyone. I have done a lot of work to the motorhome in the last 18 months of which most of the information I got here. Thanks Again
Rusty
Rusty,

I'm surprised that Gitt Springs did not want to do the job, as they have done great work in the past. I will post a note from one of our members regarding his steering issues and they were able to resolve a very evasive issue. This one was a tough one for them, and maybe that is why they shy away from these kind of things now. In any case, this was about five years ago, maybe you can show them this post and try to get them to reconsider. Your issue is likely different, but I don't see why they could not work on it, if they have done steering work in the past...
From this members experience, this seems like a top notch shop that does not gouge.

Also, when your rig is running, do you get a lot of foaming of the ATF in the reservoir (located in the rear passenger side service bay)?


Here is the two emails regarding the issue and repair done by Gitts Springs:

Back in May I took the rig to the shop where I had the king pins and bushings replaced several years ago. It is a small shop in Kent, WA that specializes in truck and heavy equipment suspension and steering. Gitts Springs if you want to look it up, they have a website. Les Schwab had recommended them when I tried to have them do the alignment and they found the king pins were two worn to do an alignment. Unfortunately replacing the king pins and alignment did not solve the steering problems at that time. This time I explained the problem, they drove the rig, recognized the problem, and went to work.

They had the rig for a week trying to solve the problem. I was getting a little concerned about what the bill was going to be with all the trouble-shooting work that seemed to be going nowhere, but I as assured that their shop policy was that they don't charge for trouble-shooting, only for the actual repair once they figure out what the problem is.

They did increase the caster, but that wasn't really soling he problem. What they did finally find was that the steering box itself was binding, preventing the steering from returning to center. But, it was only binding when the engine was running and there was hydraulic pressure on the system. With the engine off, as it normally is when suspension and steering work is done, there is no binding. Likely this is why no one was finding the problem when I had it in other shops. Anyway the steering box was removed and sent for overhaul. The overhaul shop said the seals were all swollen up and soft, likely from exposure to stop-leak fluid of some type in the past. So when hydraulic pressure was on them, it forced them out of position and they would bind up the steering.

Now, with the steering box overhauled, the rig drives great! Steering wheel returns to center when released in a turn and I have good "feel" of the road. It no longer seems to dart off to the left or right without warning, don't find myself constantly correcting to steering it back into the lane.


Followup reply to my questions:


And yes, they did flush the hydraulic system and refill it with new fluid. This was a requirement from the steering box rebuilder for their warranty. We also discussed rebuild of both the pump and the brake master cylinder because of possible damage from the contaminated fluid, but finally decided it wasn't necessary. The contamination happened something before 2010, when I acquired the coach. So if the pump and master cylinder haven't had a problem in seven or move years, they probably aren't going to.

As for costs, I was billed as follows:

$273 for the alignment

$588 for rebuild of the steering box rebuild

$573 labor for R&R of steering box, flushing the hydraulic system, and replacing front brake pads.

Their labor rate is $95/hr. They worked on it for a week trying to figure out what the problem was, but like I said before their policy is that don't charge for troubleshooting time. They consider themselves experts on suspension and steering, so their customers shouldn't have to pay them to figure out a problem.

Caster on the alignment was increased to 5-7/8 degrees left side, and 6-1/2 degrees right side. I asked how you can get different caster angles on each side with a solid axle, and they said that within a small amount the axle will twist some with different shims when weight is on it. I think they started with the alignment and increasing caster to get the steering to return to center, but didn't get the results they needed causing them to check further for binding in the system. That is when they finally found the problem with the steering box. So, still not really sure if I actually needed the increased caster or not, but it drives nicely now. Narrow, twisting, Hwy 101 along the Oregon coast was not problem. South of Seaside, there was a 30 mile detour off 101 on an even narrower, twister highway, with semi trucks coming from the opposite direction, that was also no problem.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
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