Spartan chassis "thunking" when braking

[Robsons]

I've looked through most of the Spartan threads and haven't seen anyone post this issue with out 2009 Newmar Allstar. It has a Spartan chassis.

When I put first put the brakes on to stop at, say, a stop sign, both from brakes make a loud "thunk". They seem to work fine and I don't feel any issues stopping but it bugs the heck out of me.

I had the rig in to have it checked out but they didn't find anything and the mechanic said it might just be the brake springs being new and to give it a few thousand more miles so see if they loosen up.

I know that's not a lot to go on but wondering if anyone has any ideas...

[Avalondanes]

Sounds like maybe the slack adjusters. How many miles on rig? Which chassis?


Richard

[BCook57]

I've noticed the same thing on my 07 DSDP 4307. Still does it occasionally, but not all the time. I now have approximately 17,000 miles. I'll watch the thread to see if you learn anything new.

[Raca-roni]

I had a noise in the rear of my coach for sometime. At first I also thought it was my brakes. When I was at JOSAM Alignment Shop in Orlando, FL they found the problem and showed it to me. Are you ready for this? The U bolts on the right rear side of my rear end were loose. there was a air gap under the bracket and the lower part of the rear end housing of about a little larger than1/4". Big enough to slide your finger in. All fixed and no more noises........
They do a full chassis/suspension checkout prior to starting to align all three axles on the coach. What a difference driving the coach now. I thought it was O.K. as it was. Not!

[Ann n Gene]

Those loose u bolts sound like a very likely culprit on any coach making that noise for sure. It does not take much slack to get that clunking sound. I would recommend that you check that idea before doing anything else.

[AFChap]

I have a Spartan Mountain Master Winnebago version chassis. Mine is an '02 chassis on an '03 coach w/ about 60k miles.

I have the same "thunk" as described by Robson. My noise always is clearly on the right front. When the clunk happens, which is on firm braking, it does impact braking power just enough to feel a slight tug on the steering wheel.

I too have had the chassis checked out more than once when being serviced, and no one has found anything apparently wrong.

[akadeadeye]

We have a 2009 Allstar with 3,600 miles on it. We do not have this problem. I assume you have contacted Newmar customer service direct, besides contacting the dealer. Sometimes the techs at Newmar can offer advice you can't get from a dealer.

Good luck.

Don

[Roadking]

WHen I got my rig I read most, ok some, of the manuals . I noticed there were several warnings in the operation manual and the axle manuals (meritor and reyco-gramming) about checking the torque on the lug nuts and key suspension components like the spring hangers and drag links. I think lug nuts were to be checked in a few hundred miles and axle components were to be in a few thousand miles. Sounds like the manufacturors excuse to deny any assembly fault issues. No I didn't check mine.

[AFChap]

Had my annual chassis service a couple of weeks ago at a Freightliner shop. When telling the service writer what I wanted checked a tech overheard my description and said "slack adjusters ...they need to be lubed frequently." In my case, they also needed to be adjusted ...ticket says "brakes adjusted." I didn't hear it every time I braked, but haven't heard the "thunk" yet in the couple of times I've driven the coach since it was serviced.

[aztortuga]

When we got our 2005 MM chassis MH, I noticed a "thunking" sometimes when I would brake. Two dealers could not find the source. One day while under the rear of the MH I moved the rear mud flap back and forth--noticed a thunk. Examination showed that when this rear mud flap would swing toward the front of the coach the mounts would hit the side wall. I re-attached the mount so that this was minimized, and my brake thunk went away. Hope yours is so easy to remedy.

[AFChap]

Even after special attention to the slack adjusters on the last service a few months ago, mine still "thunks" when I brake firmly. The sound is definitely in the right front and there is a noticeable change in braking power when it occurs.

[Dagwood]

AFCHAP It could also be your S cams if you have drum brakes. Sometimes a rough dry spot will hang the roller just long enough to make a thump when it goes past Also some air chambers can do the same. Get someone to operate the brakes while you watch. I would definitely get that fixed. It is also recommended to replace the same parts on both sides if you have to change anything. Good luck on this.

[David K]

Paul, I have the same thing happen on mine --- I have a 2002 Ultimate Advantage on a MM chassis. Hard braking -- noise from the right front and then a slight pull to the right. Only happens when breaking harder than normal -- I have been told the slack adjustor on that side but, I still wonder. Brake linings are OK -- they have been checked ---- another of the unanswered mysteries of the MH.

[Robsons]

Hey all,

I'm just back from our 6 month road trip around the country. I think the thunking is gone or at least significantly reduced. We had several things checked and rechecked while we were on the road and I can't say for certain what the final solution was. Here's a summary of what we did...

About 3 weeks into our trip, we stopped at a shop suggested by Spartan in Jacksonville. The replaced thrust washers and lubed everything. Confirmed that nothing dangerous was going on but couldn't figure out what the issue was. The tech thought that it was an issue with the big spring in the brake assembly that would eventually "wear in" once we put more miles on her. Thunking continued for the next 15,000 miles without incident although a bit annoying.

At the factory in Nappanee, we stopped for a few items (both repair and warranty) which included tightening the front suspension and tie rods, etc and lubing everything again. This definitely reduced the thunking noise during initial braking action although not completely gone.

All in all it didn't cause us any real trouble. I got used to it I suppose and filtered it out of my conscience.

DR