Montana Front End Clunk Pictures


97speedy
03-19-2009, 09:07 PM
Had a clunk in the front end on my 2002 Montana when turning right into the street from any driveway. Checked all the front end parts all good and tight. About a month later I was getting the same noise on the left side but not as harsh. I grabbed a flashlight and looked closely at each end of the stabilizer bar and saw identical cracks in the same spot. I removed both of the stabilizer links which go from each control arm to the stabilizer bar. Did'nt even have to test drive the van as you can see from my pictures. A broken / cracked SB the links were holding both pieces of the SB together, the noise I heard was the pieces opening and then closing giving me the "CLUNK". I test drove the van anyway and no more clunk. Going to install a soild SB and new control arms friday. Pictures may be better on my links.
http://i714.photobucket.com/albums/ww143/97speedy/CrackedSwaybar2.jpg
http://i714.photobucket.com/albums/ww143/97speedy/BrokernSwaybar.jpg
http://i714.photobucket.com/albums/ww143/97speedy/CrackedSwaybar.jpg
http://s714.photobucket.com/albums/ww143/97speedy/th_BrokernSwaybar.jpghttp://s714.photobucket.com/albums/ww143/97speedy/th_LeftFrontControlArm.jpghttp://s714.photobucket.com/albums/ww143/97speedy/th_RightFrontControlArm.jpg

http://s714.photobucket.com/albums/ww143/97speedy/th_CrackedSwaybar.jpg
http://s714.photobucket.com/albums/ww143/97speedy/th_CrackedSwaybar2.jpg

merc81
03-20-2009, 07:59 PM
I'm confused by what you are going to do. The stabilizer bar is split on the ends like you show in your photos. A new one is going to look exactly the same, with the left side half facing up, the right side half facing down. That's the way its made. There are then stabilizer shaft links that mate to the bar half and form a complete bar that appears when dirty to be one piece. Its not broken.

It may be that you need new hardware on the shaft insulater and bolt/nut pins, but its hard to see what replacing the stabilizer bar is going to do for you.

If you remove the bar connection as you say that you tried, then the wheel suspension has no support to lift it when a depression is encountered on the road (pot hole). It might not clunk anymore while free floating that way. I suspect the clunk you are getting is from bad/worn rubber grommets in the lower control arm (A arm). That's the lower piece where the ball joint under the wheel is attached. It has two pivot points, front and rear that are buffered by heavy rubber insulators. These are the lower control arm bushings and they are not fun to change. If worn, the control arm will knock against the frame when you hit bumps. Dropping off the stabilizer bar connection may (or may not) stop the knock. I never tried that to find out.

Looking at your photos, it appears you took an excellent shot of a bad A arm bushing. I'd say that's what you need to change, not the stabilizer bar.

97speedy
03-21-2009, 10:43 AM
The swaybar is rusted inside and broken. What I did was take out the links. As I said in my first post the noise started on the right side then it started to make the same noise on the left, well the only thing in common is the swaybar so by removing the links you in a sence remove the swaybar and the noise was gone even with those bad lower control arm bushings as shown. I replaced both arms and the sb, now the front end is nice and tight with no noise. Also the new sb is soild not hollow like the original one and the ends are forged not stamped and pressed together. Check the link
http://i714.photobucket.com/albums/ww143/97speedy/Rusted.jpg
http://i714.photobucket.com/albums/ww143/97speedy/Rusted2.jpg

1999montana
03-21-2009, 07:59 PM
I replaced the lower controls arms for the very reason your pictures show. The lead bushing on both sides had separated from the control arm. Stupid design; - should have been a spool bushing just like the rear one. How many cars has GM built with lower control arms with two spool bushings do you think? - how about millions.

The OEM sway bar is actually a piece of tempered pipe that has been pressed on both ends and a hole punched through for the links.

The torque or twist from one side lifting while the other pushes down is so severe side for side, that eventually the pipe breaks in exactly the places yours and mine did.

I took my sway bar out, cleaned up the pieces with a wire brush attached to my grinder and then clamped the sway bar ends in a vise. Using my MIG welder, I re-welded the two halves together on each end, then went all around the inside and outside of the ends with a bead to finish it off. After a little grinding and polishing, and a coat of rust paint, I reassembled it and the noise went away. That was 4 years ago...still going strong.

The clunk can also occur due to the angle of the shocks in the upper shock mount. As the wheel is turned on its axis, the camber angle changes. To allow for this, the mount has a certain amount of give in it. But, unfortunately, the give also allows the bores on the shocks to wear and eventually the shaft inside the shock will actually shift as the wheels are turned left to right.

You can sometimes see (and feel) this clunk happen while the vehicle is stationary. While someone turns the wheels left to right watch the shock mount from inside the engine bay (after dark with a flashlight).

Also, the clunk can be felt if you hold the coil spring or the shock as the wheel is being turned. What you are seeing and feeling is the shock re-centering itself under the centerline of its axis as the camber angle shifts from straight ahead to right or left.

merc81
03-23-2009, 06:25 PM
Those are great photos you took, thanks for the effort to show us what you are dealing with. Your bar ends do indeed look very rusted, but they don't appear any different than any of the ones I've seen other than the rust. I don't think those are broken, at least not on the ends you are showing. On all three of my vans, the ends are exactly like your photos except no rust...the clips are separate just as yours are and the bars are hollow.

Can you post a photo of the replacement bar and tell my where you obtained it? I'm interested to take a look at a solid bar myself as I have one van that seems to 'hop' a bit on bumps and I'm thinking its a weak bar.

I've replaced the struts, springs, bearing plates, etc on lots of the vans and never changed out the sb on one.

Thanks,
John

97speedy
03-25-2009, 03:10 PM
Look at the pics. One is of the piece that broke off which in theory would be one half of the bar end. One pic shows a good end and the last one shows what the broke end would look like. I got mine at Rockauto.com $102 delivered that is for the whole kit bushings, links, new bolts everything. Check the link.

http://i714.photobucket.com/albums/ww143/97speedy/Brokentop.jpg
http://i714.photobucket.com/albums/ww143/97speedy/Leftsideintact.jpg
http://i714.photobucket.com/albums/ww143/97speedy/Rightsidesplit.jpg

https://www.dormanproducts.com/documents4rb/2008ss/2800082SwayBars.pdf

merc81
03-25-2009, 08:53 PM
Again, all I can say is that all three of my vans look exactly like your photos only they are not rusted. It could be that all three of them are also broken. Certainly the replacement pdf you linked makes me think that.
The GM manual is of no use for this question because it shows only an outline form of the bar and never details the end sections. The manual does describe replacing the stabilizer shaft link and also talks about the stabilizer shaft insulators. The reference doesn't make clear that the ends are split or not.
If they are not supposed to be split, then I have never seen one that isn't (pdf link claims 75% failure rate!) and mine look so perfectly split with no rust that its hard to see how it got that way by itself.
I'm starting to accept what you are saying, I'm just a bit slow on the uptake since I have such a fine set of examples here :redface:

Chucky cheese
11-06-2009, 10:49 PM
Had the same problem on my venture as you have with the same broken piece on the sway bar and it would rattle over bumps. Did the same thing as one of the earlier posts and MIG welded mine back on and all around the split and has been fine ever since. But for ultimate repair the solid sway bar was the best way to go, I was just cheap and didn't want to invest the cash. In the old days sway bars where solid none of this hollow pipe crapy stuff, any way good stuff glad you fixed it.

shadetreewannabe
01-03-2010, 10:45 PM
I replaced my swaybar with a solid one from rock auto,both sides of mine was brocken..1999 montana Ext.

RoyGalam
04-21-2011, 11:28 AM
To 97speedy: I really appreciate the work you did with the photos to help me understand the clunk problem. To all: Can I replace lower control arm bushings easily or is it less hassle to replace the complete frame?

1999montana
04-21-2011, 09:57 PM
To 97speedy: I really appreciate the work you did with the photos to help me understand the clunk problem. To all: Can I replace lower control arm bushings easily or is it less hassle to replace the complete frame?

May be less costly to replace the bushing, but in the long run, you will eventually replace ball joints too, so replacing with a new lower arm is a lot cleaner and easier, requiring no special tools.

I replaced the ball joints in the old arms once, and it was a PITA. If you decide to replace the bushings, they have to be pressed out and new ones pressed in. I think the spool bushing can be replaced too, but it may not wear as quickly as the front 'hockey puck' bushing.

Note the pics from 97Speedy. That is a pair of bushings waiting to disintegrate.

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