Workhorse P32 Front Suspension

[Mark_K5LXP]

I'm exploring options for repairing the front suspension on my 2005 Itasca/P32 Workhorse chassis.

The specific issues I'm having are the lower ball joint seals are disintegrating and they're not greasable joints, so those are pretty much done. The other more problematic issue is the lower control arms are cracking in the pocket the coil springs sit in. [Photos below]

At some point the previous owner of my RV had SuperSteer springs and bellcrank installed. I don't know when or how many miles ago but the cracks have appeared in just the time I've owned it, about 3 years and less than 4K miles. Shown right on the SuperSteer spring installation guide is the caveat, "SuperSteer does not warranty lower control arms that crack or fail" so it seems this is not a new or unusual issue. I contacted SuperSteer and they responded but have little to offer in terms of any remedy or problem mitigation. In my opinion this is a giant safety issue (catastrophic failure) and the hazards of using these springs should be more prominently stated but that's a separate discussion.

Looking around at various Workhorse sources it appears I can source OEM grade replacement parts. But I am leery of simply replacing the broken and worn parts and expecting that the same issue won't happen again. I likely won't be reusing the SuperSteer springs, in my mind having a "stiffer" spring vs stock isn't a solution if the load isn't changing (which in an RV the load doesn't change much), and doing so increases stresses to other components. In my mind the "lightest" spring you can get that doesn't exceed the full excursion of the suspension travel in concert with the right compression/rebound rate shock would net the best ride and keep the tire in contact with the road, not a "stiffer" spring unless the OEM spring is bottoming out all the time (does it?). No aftermarket spring supplier has data on their springs to do any kind of meaningful comparison to help select the best one for the application.

My question to the forum here: is anyone aware of either alternative (more "robust") components, or component configurations that is more durable than OEM? Any specific insight as to spring and shock combinations that are better matched? I'd entertain an air spring retrofit but just like control arms there just isn't much out there for the P32 IFS chassis. But maybe there's something out there that might be "close" or integrated with some modification without having to spec something from scratch?

Barring some unknown alternative seems my only option for this increasingly orphaned chassis is to R&R with what I can find and I get what I get, but just throwing the question out there in case someone's gone down this road already and had a solution figured out.

Mark B.
Albuquerque, NM

[edgray]

MARK: Please correct me if I'm wrong, but my understanding is that the SuperSteer springs are much more powerful than OE springs so they can replace the need to have air bags inside the OE springs, which I assume are "weaker" than the SS springs. Your pictures seem to show air lines going to the center of the control arms-are air bags inside the SS springs???

AFAIK, ALL the P32 chassis came with air bag "assisted" springs. I'm GUESSING the air bags allow "less" concentrated contact pressure on the control arm at the point(s) of spring contact.

IF you have decided to replace the control arms with new, and don't want to re-use the SS springs, that implies you would be willing to return to a stock suspension and that should included the air bags.

For genuine WCC OE replacement parts, I always recommend you visit: www.URVP.com

[n2zon]

Originally Posted by edgray

MARK: Please correct me if I'm wrong, but my understanding is that the SuperSteer springs are much more powerful than OE springs so they can replace the need to have air bags inside the OE springs, which I assume are "weaker" than the SS springs. Your pictures seem to show air lines going to the center of the control arms-are air bags inside the SS springs???

AFAIK, ALL the P32 chassis came with air bag "assisted" springs. I'm GUESSING the air bags allow "less" concentrated contact pressure on the control arm at the point(s) of spring contact.

IF you have decided to replace the control arms with new, and don't want to re-use the SS springs, that implies you would be willing to return to a stock suspension and that should included the air bags.

For genuine WCC OE replacement parts, I always recommend you visit: www.URVP.com

I don't know whether they all came with air bags or not.

However, in another context, I ran into a GM engineer who worked on the P30 suspension. Someone else was annoyed by the additional complexity and need to replace the air bags from time to time. I mentioned that, from a packaging perspective, there wasn't room to either make the springs longer to allow the use of larger diameter spring wire and increase the spring rate that way. The GM guy immediately said, "That's right!" It was a vehicle packaging decision, he said, to preserve the space over the suspension for other things, like a flat floor, without having to raise the entire coach relative to the chassis.

I suspect there was an element of cost and reliability involved here, too. You can probably get higher spring rates in the same spring wire size, but it might involve more-expensive wire or heat treating. No matter what, though, the stress on higher-rate springs is higher than the stress on lower-rate springs. The most-stressed part of your suspension? You guessed it. The springs. If they were thought to be prone break more often, GM would look for other alternatives.

As a bonus, the air bags give you some control over the front wheel rate, so you can adjust their pressure to get the ride/handling tradeoff you like best.

I also don't know why the springs you have might induce cracks in the lower control arms. As Ed suggests above, I'd look at whether they are loaded the same amount in the same places. If the suspension originally had air bags, a lot of the load was borne inside the ID of the stock springs. In any case, new control arms alone might not solve the problem, just kick it down the road a bit. Appropriate reinforcement, or reverting to the OEM design, sounds like a better long-term solution. What's "appropriate"? Damifino. A MechE I am not.

[Mark_K5LXP]

Originally Posted by edgray

my understanding is that the SuperSteer springs are much more powerful than OE springs so they can replace the need to have air bags inside the OE springs,

I don't have specific knowledge of that. This is how I got the thing. I turns out that the tubing or fittings leak and will only hold air for a day or so and I've only tried the airbags filled a couple times in all the trips I've taken so far. There's a subtle difference air vs no air but not enough to be compelled to bother with it for the most part.

AFAIK, ALL the P32 chassis came with air bag "assisted" springs.

An "air spring" is shown in my WH chassis manual. Mine are not the originals but guessing there isn't much difference with those.

I'm GUESSING the air bags allow "less" concentrated contact pressure on he control arm at the point(s) of spring contact.

I would also guess that would imply there is contact between the air bag and upper/lower control arms, but I'm not sure that's how they function. It seems when pressurized the bags "squeeze" inbetween the coil turns and offer some resistance to spring compression. Maybe there's some contribution of force at the ends but if there is, it isn't much. Guessing the primary effect is over the length of the air bag and not the ends.

IF you have decided to replace the control arms with new,

It doesn't seem I have much of a choice. It's coming apart to replace the ball joints so can't see reinstalling a busted control arm. In a perfect world I'd pick a "better" one but it's looking more and more that stock is going to be my only option and maybe not even OEM but a knockoff.

that implies you would be willing to return to a stock suspension and that should included the air bags.

I want to go with whatever solution doesn't break things. I have a pretty compelling data point that suggests the super springs are not compatible with OE control arms. It's flawed logic to replace the control arms and wish they wouldn't break again. I've got to change something and if it isn't for a different proven solution or a step back to stock, I'm not sure what else I can do.

For genuine WCC OE replacement parts, I always recommend you visit: www.URVP.com

They're on the list, just need to decide what the springs will be and if there are options for ball joints. I don't like the "sealed" ones, prefer greaseable.

Mark B.
Albuquerque, NM

[Mark_K5LXP]

Originally Posted by n2zon

I don't know whether they all came with air bags or not.

Yeah, per above they're shown in the WH documentation.

Someone else was annoyed by the additional complexity and need to replace the air bags from time to time.

If that were my only problem I'd call it a good day.

It was a vehicle packaging decision, he said, to preserve the space over the suspension for other things, like a flat floor, without having to raise the entire coach relative to the chassis.

I get the design tradeoff thing. Having worked in design and manufacturing engineering for a few decades I totally get the concept of shoot the engineer and release the product. In a perfect world there'd be an aftermarket solution but that requires a demand, and being an orphan chassis it's a safe bet that's not going to happen. So it is what it is.

You can probably get higher spring rates in the same spring wire size,

That's kinda what I'm looking at now but data is hard to come by. Would be useful to compare the OE spring with other aftermarket and even made to order but it appears not may people engineer their own suspensions. So it's going to come down to what sources I can find and a WAG which one to try. Worst case is to swap them out for something else if they don't work out which is a process I've already done on other vehicles, so not the worst thing to do. Maybe the stock configuration is prone to failure too but in my online searches I didn't find any examples of that. Pretty much on my own for this one.

The most-stressed part of your suspension? You guessed it. The springs. If they were thought to be prone break more often, GM would look for other alternatives.

I've never had a spring break but I have had them sack out. I would think the lower control arm would be the weak link with all the shock and vibration but I'm not a ME.

the air bags give you some control over the front wheel rate, so you can adjust their pressure to get the ride/handling tradeoff you like best.

These aren't like air ride suspension bags, per above the difference between empty and max is discernable but not marked or even improved. Just different.

I also don't know why the springs you have might induce cracks in the lower control arms.

My guess is point stress in the pocket from the sharp end of the spring.

I'd look at whether they are loaded the same amount in the same places.

Valid point but there's little I can do to change the shape of the end of the spring or pockets they sit in. The top and bottom pockets are "polarized" so the ends of the spring are specifically located, after that it is what it is.

a lot of the load was borne inside the ID of the stock springs.

I think if that were true when the air bags were full I'd see the ride height change but there's no change with these. Seems they offer a little bit of dampening/shock absorbing action but nothing in terms of additional lift.

new control arms alone might not solve the problem, just kick it down the road a bit.

Agreed, something has to change to expect a different outcome.

What's "appropriate"? Damifino.

Which is why I'm here, I want to find out if there's a clear and present solution before I go off into the weeds on my own instead of finding out after the fact there was a better solution. Just coming up with options, I'll pick what looks the best and see how far down the road it gets me.

Mark B.
Albuquerque, NM

[n2zon]

I do agree that the air bag only solution, as in our Tiffin, is an entirely different beast than air bag assisted coil springs. However, on our P30 the ride height difference between empty and pressurized air bags was 2-3". Very noticeable. Also noticeable was the difference in handling and ride between, say, 70 and 100 PSI. 90 or so PSI seemed to be a reasonable sweet spot for us for ride comfort and handling. Below 60 PSI or so, turn-in was really mushy, the suspension would bottom out, and the driver's side tire would eat into the wiring harness in the wheel well (grrr....Winnie could have routed it out of the way with no additional cost!!!). If the spring rate of the SuperSteer springs is a lot higher, these differences might be less noticeable than with the stock ones.

I have had broken coil springs several times. Fortunately, they were all in cars! Usually, for our cars, it's been a coil near the end that breaks, but once one broke in the middle. That one was, um, "more exciting." This is much more common in the "salt belt" than farther West.

If it were mine, I'd want to go back to OEM *or* reweld and reinforce the lower control arm with something like 1/8" or even 3/16" plate shaped to fit and welded in and a (hard-ish) neoprene pad to spread the load on both sides. But like I said, an ME I ain't. And, whatever you do put there will raise the ride height a bit, though I doubt the difference will matter much. If you're not a lot better at fabrication than I am, you'll need someone to do this for you, too.

The OEM solution, in my opinion, isn't bad. The major drawback was that it leaked down over several days, so you have to have access to compressed air to leave the driveway or the campground. (I carry compressed air anyway, so for me this was no big deal.) It looks like your air assist springs are still there from the pictures.

[David 70]

When I bought my 2001 Adventurer the air bags would not hold air. I had them replaced, about $1200, which included an alignment of course. When I got it back I saw the air lines up in the hood area. I thought, oh good, no more crawling under the coach. They kept loosing air after about 2 or so days and checked all the fittings to no avail. I finally decide to remove the lines and for three years now they have not lost any air. Remove the lines and see if that helps. I have 70,000 miles on it and do not see any failure of the bottom a-frame. I keep 80lbs. in the right and 70 in the left trying to help a bit with the lean of the road. I haven't experimented much because this seems to work for me. If it were mine I would weld a piece across the crack and keep an eye on it. I wouldn't think it is going to be one of those times when it would go from ok to falling off in a matter of miles. The crack I would say is at the end of the coil and that is where the most pressure is.

[George Schweikle]

Well.... a nice story but my take on the P-30 & early Workhorse front suspension is that it and the entire chassis is just a money saving derivative of the Chevrolet step van, which really just has the generic pickup truck front suspension.

That said, my solution back around 2005 was to install a big Helwig leaf spring kit that attaches sideways to the front cross member, connects to the two a-arms and is adjustable for tension. I did this to replace the troublesome air bags. I installed mine after a recommendation from the Safari TREK forum. This didn't raise the front a whole lot, but eliminated the air bags. Unfortunately, a quick google search didn't find that this product is currently available.

Originally Posted by n2zon

..... I ran into a GM engineer who worked on the P30 suspension. Someone else was annoyed by the additional complexity and need to replace the air bags from time to time. I mentioned that, from a packaging perspective, there wasn't room to either make the springs longer to allow the use of larger diameter spring wire and increase the spring rate that way. The GM guy immediately said, "That's right!" It was a vehicle packaging decision, he said, to preserve the space over the suspension for other things, like a flat floor, without having to raise the entire coach relative to the chassis..

[CamJam1]

The good news is that the control arms are cheap. Lower control arms are as little as $25 on Rock Auto and even the top of the line Moog heavy duty "Problem Solver" arms are only $125 complete with bushings installed. It would be interesting to know what the difference is between the regular and heavy duty control arms. Just the writing on the box perhaps… though I do know Moog's Problem Solver line often incorporate improvements to the original design. In the case of my PT Cruiser they replace a rubber bushing that's prone to failure with a full ball metal stud.

I had a P30 for a number of years and had no real complaints with how it rode or handled except for the front suspension crashing on the occasional bridge transition.

[Mark_K5LXP]

Originally Posted by CamJam1

The good news is that the control arms are cheap. Lower control arms are as little as $25 on Rock Auto and even the top of the line Moog heavy duty "Problem Solver" arms are only $125 complete with bushings installed.

But nothing listed for the P32...

Mark B.
Albuquerque, NM

[Isaac-1]

Let me preface this to say that I have a 2002 P32 chassis coach and upgraded to SuperSteer Springs when my coach needed new ball joints a couple of years ago. I feel the SuperSteer springs are a noticeable improvement on ride, and make the ride much LESS harsh than the factory springs with factory helper airbags. Given this experience, I can see no reason why Super Steer springs would have a higher tendency to cause cracking in the lower arms than factory springs, as long as they were installed clocked correctly.


Now down to the next point, how do you know you have Super Steer Springs, do you have the receipt from when they were installed? I ask because the factory springs and the Super Steer springs look nearly identical, and they are both painted blue, as Workhorse springs from 2001 - about 2005 were painted blue from the factory, this is due to a small number of incorrect springs which were installed / recalled in 2001. Therefore Workhorse simply painted the corrected and all new springs blue for a few years, before going back to black springs during the 2005 model year. It is probably not the exact same shade of blue, but is close, and once you consider fading over the years is nearly indistinguishable.

[CamJam1]

Originally Posted by Mark_K5LXP

But nothing listed for the P32...

Mark B.
Albuquerque, NM

Sorry... my bad! I tend to lump the P30 and 32 together, but obviously there are some differences and you're correct that Rock Auto lists very little for a 2005 P32.

[David 70]

I have noticed on my 2000 P32 that the front end has been widened by welding support pieces to make the front track as wide as the rear. Ultra RV tells me the 2000's, although they say workhorse, they are left over GM that Workhorse bought and resold. I would have to believe them as they are the go to people as far as I know. I've had no problems other that replacing the air bags right after I got it 5 years ago. It drives good other than wind and passing semis which I expect in a lighter on like it is. I put the sumos on the rear this fall as the bump stops were shot. I haven't had it on the road since so will know more once I do. I would think they would help.

[Mark_K5LXP]

Originally Posted by Isaac-1

I feel the SuperSteer springs are a noticeable improvement on ride, and make the ride much LESS harsh than the factory springs with factory helper airbags.

I've seen mixed reports about this. The direction I'm going is to use an OEM size spring with airbags because I need to change something if I expect a different outcome. I will keep the SuperSteer springs to the side in the event the OEM outcome is bad enough to make broken control arms a better alternative.

how do you know you have Super Steer Springs, do you have the receipt from when they were installed?

I have zero prior owner maintenance and repair documentation. But the SuperSteer logo printed on the spring was a pretty compelling clue.

Mark B.
Albuquerque, NM