P-30 Sway Bar Bushings Replacement

[WrigleysBraveWin]

Herd a clanking noise on driver's side front end, sure enough there is at least one issue causing noise and I'm taking to truck mechanic next week   ...  Of the four Bushings, one is gone and two have been replaced but work is not up to par, thus I'm replacing all four Bushings .... Questions Are:

Should we go ahead and replace the tie rods, stablizer bar and / or what other parts would be a good investment so long as we under there .... AND SECONDLY ..... What brand of Sway Bar Bushings are recommended - what is best?

[wae]

The stabilizer bar or sway bar is basically a spring that connects the two wheels to each other to assist during weight transfer events on the chassis to keep both wheels firmly planted on the ground and limit the amount and effect of body roll.  It's not really a wear part and if it isn't bent or otherwise damaged, there would be no reason to replace it unless you feel like a stiffer or lighter bar would help the handling characteristics.  If this was a car, we might talk about understeer and oversteer but on a working chassis like this, my semi-educated guess is that there's not much gain to be had from playing with bar sizes.


I like the Moog swaybar bushings, myself.  They used different diameters on P30 chassis so you'll want to measure yours with a caliper to make sure you have the right size.  Mine was the 1.25" bar so I got two Moog K6476 kits for about $10 each so I could replace all four bushings.  Pro-tip:  Bolt up the control arm side first, then use a jack to push the swaybar into place to bolt up the frame brackets.  These are poly bushings that won't squeak or be too stiff, but will last much longer than regular rubber.


As far as things to do "while you're in there":  You do not need to lift the front end in order to do the bushings, so it's not like you'll have anything else apart just to do the bar bushings.  It's not a bad idea to put the front end in the air, though, and verify that there isn't anything loose -- you've got wheel bearings, ball joints, control arm bushings, and the tie rods to worry about there, primarily.  If you've got air bags in your springs, you might check to make sure they're sealed up.  Your shocks should not show any evidence of leakage, either.  I believe that Chevy specifies a maintenance interval of 12k miles to re-pack the front wheel bearings.  In theory, if properly lubricated and not externally damaged in any way, those bearings should last forever.  My own opinion, however, is that if you don't have proof or knowledge that those bearings have never been damaged and have been lubed every 12-15k miles, put new good ones in.  Something from Timken, National, Delco, or the like and use a good synthetic grease.  You're taking them out to re-pack anyway, so you're most of the way there and new ones just aren't all that expensive when you're not needing to call out the mobile mechanic to do the job in a truck stop.

[WrigleysBraveWin]

wae: Appreciate your input / tips and Moog was name I was looking for .....  Thanks!

[Rickf1985]

I had the urethane bushings in mine and since they were stiffer than the rubber they ripped the brackets clean off the lower control arms! In my opinion the best bushings for the sway bar are the stock ones. You need some give with a bar that thick and brackets that thin. The P30 chassis uses two idler arm assemblies, one on each frame rail and these are always bad. If you look straight up at it and have someone rock the steering back and forth you will see the bottom pivot moving side to side. It takes very little movement there to equate to a lot in the steering geometry. There are aftermarket ball bearing units to replace them. The originals are no longer available. Between this and a loose steering box (internally), they are the main problems with the P30 front ends. That and people that do not know how to properly align them.

[WrigleysBraveWin]

Coach tracks straight and even wear on tires but I do have some play in steering wheel - Sounds like you hit nail on head with the steering box .... How much of a job is it to replace the bearings inside the box?

[Rickf1985]

Replacing the bearings in the steering box is a major job but usually it is nothing more than adjusting the free play in the sector shaft. I am getting ready to turn in, got one eye propped open but if you do a search on here for steering box adjustment you should come up with something. The play couls also be from the idler arms which is common.

[CapnDirk]

A reasonable test for where the slop is is to have someone gently (with engine off) turn the steering wheel left and right just to the "point of resistance".  The loose play is somewhere in the mechanical things, and having the engine running and the power steering helping masks where the slop is.  Get under it and you can look at whats moving and whats not while they are doing it.


If they are going from left and right resistance and you see nothing moving, the slop is likely in the steering box.  From there you can see what tie rod, idler, whateva might have the slop.


CapnDirk your slop guy this evening... 

[WrigleysBraveWin]

Rick and Cap ..... Thanks for you valuable input, both are making me smarter .... Looked on this forum and could not find anything on steering box but a quick check of the web and my first visit was to: http://jdfinley.com/steering-play-adjustment/ where I discovered my issue maybe just a simple adjustment .... Armed with some knowledge I'm off to a "trusted mechanic" Monday to get this rig in tip-top shape, I hope!

[Rickf1985]

Cap, you need to put a little more "umph" into it then "just a little resistance" to see where the play is. Especially in the idlers. There are many hundreds of pounds of force on those joints and linkages when driving so that is what you have to duplicate.

[CapnDirk]

X2 on what Rick said about going rubber bushings.


Rick:  My intent was to get the slop out of the gear box first (if any) then be more firm in the turns of the wheel to see what else shook out.  May not have been clear on that.

[WrigleysBraveWin]

Changed out rear leaf springs and put new Bushings on front Sway Bar .... Got some Moog oversized Bushings on Amazon for just $15 a set and they are nice and big verses original ..... the new leaf springs lifted the rear end about 4-5" and even before I left the parking lot I could feel the difference ..... The spring work was not cheap but after 23 years of wear it needed new leaf springs ....

Next month new shocks and some front end / steering box work is scheduled!

[Rickf1985]

Lifting the rear end that much would say to me they used the wrong springs. In your pictures it was not sagging and if it was it was not noticeable. It must be sitting rear end high now which is not god. That is really going to screw with your front end alignment not to mention you are going to have to block up the front wheels at every campsite to get the fridge level. Was this done at a spring place or a regular shop?

[WrigleysBraveWin]

From the side view does not look like much of a raise but the rear bumper view raise is notable ....

Work was done at a spring shop, Aurora Spring or ATC as they are known today at 308 NE Industrial Drive, Aurora, IL 60505 ....

ATC originally started as a Spring Shop but have expanded to other Truck Services like hoses and front end work .... Issue having them do any other suspension work is they have to use their suppliers and won't install say any shock other than Monroe Shocks so I had them just do the leaf springs -  I have dealt with the boys at Aurora Spring for over 35 years, we did their roof back when and have had many of our truck springs worked on their, From 1800 Series International Dumps, Stakes to our PU Trucks .... Guys know their biz, they are usually 7-10 days out, they stay busy ....

We do have a RV Suspension Speciality Shop setup to do evaluation of entire system, so that's our next stop and I've got a feeling it won't be cheap!