Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Carl Cox on September 22, 2016, 10:47:57 pm

Title: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Carl Cox on September 22, 2016, 10:47:57 pm
While I was making a mess greasing the zerks I noticed the rear duals are eating away at the liner plastic.  On the left side I can actually see some of the inner styrofoam.  I never hear this rubbing, the tires look fine (and are correct sized Michelins 275) and am not sure how it happens.  My plan is to seal the plastic panel with 3m 4000 to prevent the styrofoam from taking on water while driving in the rain.  Anything else I should do?
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: wolfe10 on September 22, 2016, 10:49:45 pm
Check the RIDE HEIGHT.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: jcus on September 22, 2016, 11:25:22 pm
While I was making a mess greasing the zerks I noticed the rear duals are eating away at the liner plastic.  On the left side I can actually see some of the inner styrofoam.  I never hear this rubbing, the tires look fine (and are correct sized Michelins 275) and am not sure how it happens.  My plan is to seal the plastic panel with 3m 4000 to prevent the styrofoam from taking on water while driving in the rain.  Anything else I should do?
If your normal travel height is okay, it could be driver error. I leveled the coach one time at a campsite, [front bags full to raise front,
rear empty], had to move in a hurry and started up and took off. When I had moved it to another campsite smelled some rubber.
It can take a minute to two for the compressor to pump up the bags to travel height, if the tanks have bled down.
Jim
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Caflashbob on September 23, 2016, 12:04:11 am
Mine has rubbed through showing the blue foam in both rear wheel wells also.

The OEM  shocks wore soft and allowed a lot of body roll.

My extensive reading of the info here going back to the old forum has references to foretravel raising the body off of the suspension setup.  One  inch?  Steel washers?

I think I have read every post in both new and old forum to help me with our coaches issues and changes needed.

But for the reduced contact between the tires and wheel wells the center of gravity of the coach was raised a bit.


Our 97 is among the best driving coaches I have driven,  quite amazing
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: craneman on September 23, 2016, 01:28:59 am
Mine has rubbed through showing the blue foam in both rear wheel wells also.

The OEM  shocks wore soft and allowed a lot of body roll.

My extensive reading of the info here going back to the old forum has references to foretravel raising the body off of the suspension setup.  One  inch?  Steel washers?

I think I have read every post in both new and old forum to help me with our coaches issues and changes needed.

But for the reduced contact between the tires and wheel wells the center of gravity of the coach was raised a bit.


Our 97 is among the best driving coaches I have driven,  quite amazing

How would one compensate for the pinion angle being changed?
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: John44 on September 23, 2016, 05:56:34 am
Agree with Brett,verify ride height that would be a heck of alot of body roll.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Caflashbob on September 23, 2016, 09:01:37 am
Entire sub frame and axles were not altered.  Body set up one inch.  Spacers between the floor and chassis is what was posted here as the mod.

Not sure if anything needed resetting.  A production mod.  Not refitable as far as I understand this.

I replaced the shocks with the Koni FSD's as the OEM Konis had softened over 100k miles allowing tire contact.



Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: John44 on September 23, 2016, 09:18:41 am
I agree the new shocks will help with the body roll but they will not do anything either way going straight down the road or
standing still they dampen the up and down movement.Could possibly your torque rod bushings be so worn that the coach
is sitting lower from the rubber broken and worn.

Don't forget you can take the coach to HWH in Iowa and they will check the system for free.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: krush on September 23, 2016, 09:29:20 pm
Many of our FT have had tire to bottom of floor contact over the years. Might be from a really bad bump in the road, or (as mentioned) somebody moving the RV before it was aired up in travel mode. It's not a huge deal. If you want, patch over them.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: wolfe10 on September 23, 2016, 10:09:16 pm
Actually, I would suggest you DO need to patch over it to keep from having water damage.

A thin sheet of aluminum or fiberglass bedded in polysulfide is a pretty easy solution for the break in the top of the wheel well.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Old phart phred on September 23, 2016, 10:22:44 pm
Can I throw this thought out. Since a DP is backwards from most vehicles is it a engine torque loading of the left side compressing the suspension? Causing contact?
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: wolfe10 on September 23, 2016, 10:42:56 pm
I think we have identified the two most likely suspects-- agree there could be others.

1. Improper ride height.
2. Driving before ride height is achieved.
3. Trying to level on a  very out of level site with air leveling can also do it with the "high corner" lowering until contact is made.

Have never noticed a side to side transfer on acceleration in a DP-- particularly one with 8 outboard air bags.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: John44 on September 23, 2016, 10:47:06 pm
If I'm reading it right thats what the torque rods prevent,the rear on my coach has 5 seperate rods.

Throwing this question out there,what is different on the 270's thru the 320's in the suspension to get the 320 to carry more weight?
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: jcus on September 23, 2016, 10:51:49 pm
Can I throw this thought out. Since a DP is backwards from most vehicles is it a engine torque loading of the left side compressing the suspension? Causing contact?
Does not make any difference which way the engine faces, you will notice semi's that load over to one side when they take off.
I think most engineers take it into consideration when they design a vehicle.
Jim
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Don & Tys on September 24, 2016, 12:26:01 am
I believe the suspension components are the same, although the U320's came with adjustable Koni Gold Red shocks, and the U270's came with Bilsteins. The part numbers for Koni FSD replacement shocks, as I recall, is the same for all three models. I think that the only differences are the axles being of a higher rating. Being that the ride height is controlled by air springs, more weight just means higher air pressure in the air springs. The air springs for a given year (*to a certain point anyway) have the same part numbers, except the tags on tag axle coaches. The gauge of the steel is the same in the U320's and the U270's. I imagine the bolt on engine carriage is probably heavier duty on the 320's, but it would have to be a bit different anyway to accommodate the engine mounting points of the larger ISM (or M11).
Don
If I'm reading it right thats what the torque rods prevent,the rear on my coach has 5 seperate rods.

Throwing this question out there,what is different on the 270's thru the 320's in the suspension to get the 320 to carry more weight?
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Caflashbob on September 24, 2016, 10:53:20 am
The new FSD's are gold.  The old adjustable Konis were red tops. Bilsteins were blue?

My new to us older Lexus has the same shock issue that our coach with redtops had even after several adjustments.

Too much high speed compression dampening so square edges kick back and not enough low speed compression dampening for the rolling big bumps.

The FSD's fixed the coach.  So far Koni does not list a FSD's for our older Lexus.  More research is needed for the car.
Title: Re: Rubbing thru the plastic liner in the left rear wheel well...what to do.
Post by: Carl Cox on September 30, 2016, 11:30:56 pm
I finally got around to sealing the rubbed thru part of the wheelwells...only where I could actually see white styrofoam from the tire contact.  I decided to seal the panels with 3M 5200 black....using the caulking gun and latex gloves I was able to defeat gravity...oh...and I had the coach raised to max.  Looks like a good fix and I know that there is nothing tougher and more waterproof than 5200 from my circumnavigation on our sailboat...good stuff!  Strangly...the aft port wheelwell was most affected and the forward port wheelwell was also just wearing into the foam...starboard was minor.  Outer rear well was the worst...inner was barely scraped.  I will add a quick look at this area this to my walkaround routine and will be much more careful of my leveling technique.  I may even start to use blocks in my sloped parking slot so the rear wheels dont need to be touching the wells with the front airbags at max extension to achieve a level coach (mostly so we can run the fridge between trips).  I decided not to put any hard or metal liner in there as the airbags are so close and look so vulnerable to something coming adrift.  Only advice I have is try to get 5200 Fast cure as this stuff takes days to set up in the cool weather here in the Pacific NW.