Author Topic: Front Axle Bolts  (Read 5409 times)

Mike & Gail Beggarly

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Front Axle Bolts
« on: December 14, 2019, 07:35:33 PM »
Crawled under the coach to see how difficult installing a Safe-T-Plus would be. Noted probably best to have shop do it along with an alignment. Happened to look over at PS bolts and saw rear bolts loose and about 1/2” space between pad and axle. I guess this explains why I was hearing a POP after starting forward movement after being stopped. Trouble is I had it aligned in April 2016. Haven’t put but about 3k miles on it since then. Surely these didn’t just work loose. Thinking that the alignment shop didn’t get them torqued. Sure glad I looked! I am sure the axle was twisting to close the gap during braking and was popping loose again when initiating forward movement. I guess I need to increase the frequency of looking under the coach after service work. Anyone else had an issue with axle bolts coming loose or maybe better said, being left loose? I guess this could be considered a crisis averted since I found it before the Christmas trip North from FL to TN.
06 Monterey Pacifica IV

Gerald Farris

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Re: Front Axle Bolts
« Reply #1 on: December 14, 2019, 07:45:00 PM »
Mike,
It looks like a tapered shim was installed to increase caster angle, and simple tighting the bolts will correct your issue without aligning the front end again.

Gerald

Mike & Gail Beggarly

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Re: Front Axle Bolts
« Reply #2 on: December 14, 2019, 07:54:10 PM »
Hi Gerald. Thanks for your reply. I’m going to crawl under it tomorrow and tighten it down, for sure. I’m also thinking you’re correct with the shim. When the alignment shop did the work in April 2016, he called me after about 3-hours of work trying to get the caster correctly set and said he was still having problems getting it within spec. Then an hour later he called and said, “we finally got it”. The problem was on the PS. Assuming they neglected to torque it back down. Haven’t looked real close but do the shims just slip in or do the bolts go thru the shim? Hoping I didn't lose a shim. If they are thru-bolted, I guess there’s no chance as long as bolts are still in. I’m assuming the shims have holes for the bolts. Am I correct on this? Again, thanks so much for your reply.
06 Monterey Pacifica IV

Gerald Farris

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Re: Front Axle Bolts
« Reply #3 on: December 14, 2019, 10:30:22 PM »
Mike,
The shims come both ways, some have bolt holes, but some do not, however most heavy truck shims do at least have a hole in the center where the locater pin or leaf spring tie bolt is used to hold the axle in position. 

Gerald

Lonne Mays

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Re: Front Axle Bolts
« Reply #4 on: December 15, 2019, 05:18:45 PM »
I really wish I could trust service shops to do quality work, but it seems like it is prudent to inspect everything they do to make sure it was done correctly.  That is why I have chosen a diesel service shop that not only has a good reputation (they service several local fleets including logging trucks, dump trucks, garbage trucks, etc.), but does not object to lending me a creeper and letting me follow the mechanic around under the rig and watching his every move.  (I use the explanation/excuse that I'm trying to learn more about my motorhome's mechanisms and the proper maintenance thereof.  This way the mechanic is comfortable and freely shares his advice and experience, and I do actually learn some useful tips as well.) 

Lee Welbanks

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Re: Front Axle Bolts
« Reply #5 on: December 15, 2019, 05:41:23 PM »
Those shims are wrong for that front end, not all of the load on the front axle and frame are in that one little spot. They need to remove those shims and get the correct ones.
Another point: If the shop will not let you in to watch and inspect their work find a different shop. Some will state that it is a insurance issue and that's just BS.
Number one main reason I do all my on work, except tires, Lee don't do tire anymore!

Mike Shumack

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Re: Front Axle Bolts
« Reply #6 on: December 15, 2019, 07:55:48 PM »
I can't tell if the shims are wrong type or not - but they do appear to be spanning the full axle to H-frame contact area.

However, I thought it odd that the thick end of the shim is to the front. That would "reduce caster" (make less positive). Maybe that is what the alignment called for.
Usually the steering complaint is a "wandering issue" in which case more positive caster (to the limit allowed by alignment specs) is what is needed.


Eric Maclean

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Re: Front Axle Bolts
« Reply #7 on: December 18, 2019, 11:36:22 PM »
Hi Mike
Just to weigh in on the faster shim set up on your front end.Caster is the angle used to help make the vehicle self center  as the center line of the king pin is moved Carter away from vertical more vehicle weight is carried as the wheels are three left or right .
It is this carried weight that causes the steering to self center or return to the straight ahead position after turns.
May of you can remember the late fifty's and early sixty's cars with the large thin rim steering wheels and standard steering
when you turned these cars and let go of the steering wheel the wheel would spin back to the straight ahead position this was positive faster at work.
The more positive caster the better the vehicle would track in the lane or roll into a curve on a banker corner.
This caster comes with couple of down sides the first of these is as positive caster increases the front end parts start to transfer road shock from pot holes or other hazards are transfered through the suspension to the driver.
The second is that as wind load on the side of the vehicle increases the vehicle will roll off away from the wind Force this is known as wind steer and can wear a driver out in short order on a gusty day.

Now if the driver shares this wind steer condition with a safety alignment man the mechanic will some times move your caster angle closer to the zero caster mark or even into negative caster by doing this the wind steer will be reduced at or near the zero make .
If the wind steer persists the mechanic may even move into negative caster this has a very interesting effect .
Just as positive caster make a vehicle steer away from the wind Force negative caster does the opposite as the wind side load increases the vehicle will actually steer into the wind Force making the vehicle much easier to handle in windy condition's
The down side is you loose the self centering effect of the positive caster and you have to drive the vehicle straight down the road .
Our coaches are usually set up with positive caster but caster is not a tire wearing angle and can be fine tuned to driver preference.
Hope this helps to understand the relationship caster shim installation
PS    those shims would probably be ok although I personally would like to see them the full width of the support plate and have bolt holes through them the bolts should be tight.
Happy travels Eric


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