Is request for suspension engineer OK?

[scoutmstr]

I have a very specific problem with chassis difting to right and after much work, research etc am at a dead end. Is it appropriate to ask for suspension engineer assistance? If so I can post all steps gone through but it will make a very long post so I'd rather find out if above question is valid first.

[scoutmstr]

I have a very specific problem with chassis difting to right and after much work, research etc am at a dead end. Is it appropriate to ask for suspension engineer assistance? If so I can post all steps gone through but it will make a very long post so I'd rather find out if above question is valid first.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by scoutmstr:
Is it appropriate to ask for suspension engineer assistance? </div></BLOCKQUOTE>We often saw a member here that posted as "suspension engineer". He worked for DSP or Detroit Steel Products. This is a key firm that laid the ground work for engineering and manufactured a great number of suspension components for Workhorse. I haven't seen him post here in quite some time however we have highly competent chassis technicians that read these posts every day so the best advice I can offer you at this point would be to post away!

[Full-Timers]

If your chassis has been stretched, this could be your problem and Workhorse will not listen to your complaints. If they got one chassis rail just a small fraction of an inch longer/shorter than the other, you will have problems. Also there are a lot of other factors that will cause your chassis to drift including tires, alignment, load, broken/missing suspension parts, ect.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Full-Timers:
If your chassis has been stretched, this could be your problem and Workhorse will not listen to your complaints. </div></BLOCKQUOTE>Full-Timers, I wouldn't go that far. WCC will work with the owner to resolve any type of problem when it comes to chassis faults. Service may seek a reimbursement from the OEM after the WCC customer is back on the road if appropriate. Workhorse does not automatically default to a denial mode when resolving issues for their customers. I have seen the RSMs work out there and they are unusually helpful and they do the best they can.

We recently saw where a number of welds were missing inside the rail on a frame stretch and the Workhorse Service Center here in Myrtle Beach fixed the problem by coordinating with the RSM.

[Redlands Truck and RV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by scoutmstr:
I have a very specific problem with chassis difting to right and after much work, research etc am at a dead end. Is it appropriate to ask for suspension engineer assistance? If so I can post all steps gone through but it will make a very long post so I'd rather find out if above question is valid first. </div></BLOCKQUOTE>

I'm guessing your work involved alignments etc. Did your service center try switching the 2 front tires? I can't tell you how many times we have pulled our hair out just to find this as the culprit.

[scoutmstr]

OK here's the post.

2003 W-22 chassis with a Rexhall Vision 29' with couch only slide. Specifically built for me since Rexhall normally does not put that coach on that chassis. 19.5 wheels, 208 WB from WCC, not streched or modified in any manner.

I picked up the coach at the factory in Lancaster with 8 miles on it. Following has been done for drifting problem since new.

1. Henderson in OR warrantied out both front tires at 3900 miles after doing their RPA on it.

2.Aligned by International at about 10K miles 2 wheel only Reverse shim on left to decrease caster. Tires switched. No changel

3. Got Alcoa wheels and through Goodyear rep in Phoenix warrantied out one front tire and 1/2 warrantied second front tire. Currently on 5th and 6th front tire. About 12K on unit.

4. Right after #3 went to Spectrac in PHX and had four wheel alignment done. Also had diamond check on frame for parellism (Spelling) Also check hangers relative to frame&gt; everything on frame is correct. Removed 2 deg wedge from left side. Pull unchanged. Caster is 5.25left, 5.5 right Camber is 3/8left, 1/4right, toe is 1/16.

Before Spectrac tires had been balanced on Hunter Road Force after every wheel had been measured inside and outside for lateral and radial runout. Tires were not only road force but spun 180 deg for minumum weights and mounted as Goodyear and Alcoa had suggested which is different but made sense.


Tires have been swapped left to right in front on chance that tread seperation was causing the drift. No change. Drift is not always the same but is not related to crown of road or side wind. Have driven both directions on interstate same day just to chedk.

I have checked the pitman arm to pitman shaft and the marks are aligned. La Mesa did change out 2" stabilizer bar for 2.5 one but I can't see anything that would lead me to believe that was putting on side stress.

The power steering pump does not impart any twist to the steering wheel upon start with load off tires, so it doesn't appear to be a valve in the pump.

The last thing I can think of is the high point on the steering gear is not in straight ahead postion but can find no evidence that anything has been changed to cause this.

I know I can preload it by caster wedges, and with either Howard's steering or Tru-Center and not have a drift or pull but that is only masking the cause and not solving the root cause.

Currently the coach is at Echols in PHX for rear axle (under warranty). Seems from the factory (Dana not WCC) it was setup wrong so the S135 in a 17.5K loaded coach wore out in 18K miles.

So if Redlands, suspension engineer or any other master mechanic has a solution I'm all ears. As you can see, I have done a lot in the quest for the root cause.

Sorry for the long post but needed to impart lot of information.

[Redlands Truck and RV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">. Right after #3 went to Spectrac in PHX and had four wheel alignment done. Also had diamond check on frame for parellism (Spelling) Also check hangers relative to frame&gt; everything on frame is correct. Removed 2 deg wedge from left side. Pull unchanged. Caster is 5.25left, 5.5 right Camber is 3/8left, 1/4right, toe is 1/16. </div></BLOCKQUOTE>

[Redlands Truck and RV]

If your coach was here we would increase the caster "split". Right now your split is .25: Left 5.25, right 5.5. We use a .50 split. I know it doesn't seem like much but we find that a drift will typically follow the side with the lowest caster.

I suggest trying to increase the split by lowering the left or raising the right.

You also talk of a 4 wheel alignment. Does this mean you had your rear axle thrust angle checked? It's also known as rear axle alignment, we send a laser beam from the rear axle to a receiver at the center of the frame as close to the front as possible.

Did you get printout of the rear?

[scoutmstr]

Redlands,

I don't know how to pull your response into my response so I'll address this to you.

The International alignment decreased the left caster to under 4 degrees and Spectrac removed the wedge. Pull was same in both alignments which shouldn't be but is.

Yes the rear axle was checked by laser beam but no I didn't get a printout.

Spectrac did find the front axle was slightly to the rear on the right side and said they corrected it. In all they worked on it for about 5 hours while I was watching.

Could the coach be mounted on the frame at an angle to create a wind drift? I can't see it but unsure how to measure for it.

[Redlands Truck and RV]

Did you get a printout for the front? If you did please fax it to me.

909.792.0984

[Mutha]

Scoutmstr, you might want to check for a front brake caliper dragging or a frt. wheel that is not tight enough on its bearings.

Glenn

[scoutmstr]

Keith,

I did not get a printout for the front either. I got a sheet with the numbers written on it.

[Redlands Truck and RV]

Ouch!

Without a printout you don't have a record of what your settings were before or after the alignments. Someone writing down some numbers doesn't count.

This printout is the first thing a service center should ask for when trying to help solve a problem. If I remember, you don't have one for the rear as well.

You need to get to an alignment shop that is familiar with the Workhorse Chassis and has updated and calibrated equipment that can record and print readouts of your before and after. My suspicion is that you still have an issue with caster.