Vibration in the rear end...

[skater]

I've got a vibration in the rear end from about 50mph up.

It could be something as simple as unbalanced tires; I may have lost a wheel weight. But I'm afraid it's something bigger, like a rear wheel bearing or even something in the rear end...

The driveshaft universal joints are new; they were replaced when the transmission was done.

Also, the rear tires do not match and haven't for as long as I've owned it, but I was not having any vibration problems until late last year.

Any ideas?

I'm taking it camping this weekend (not far, and not fast), so afterwards I'm going to take it somewhere and have them check it. First step will probably be to check the balance on the wheels.

[Alaskan]

Having rear tires that don't match is a bad deal... most likely if you had them off and measured the circumference it would be different...thats hard on the rear end gear...

Have them all removed and checked for balance and round and put two that match the closest on the rear....

[skater]

Having rear tires that don't match is a bad deal... most likely if you had them off and measured the circumference it would be different...thats hard on the rear end gear...

Have them all removed and checked for balance and round and put two that match the closest on the rear....

Yeah, there are three that match, but one is different due to a blowout. I hope I haven't already done damage to the rear end. Like I said, though, I never had a problem until last fall - but it's possible they were okay until I started messing with the inflation pressures.

What I'd like to do is get them to find a tire to match the odd one (since it's the newest) and put that on the other side rear. Then take the one they pulled off and make that the spare - the spare I have now is completely dry-rotted and shot. If I did have a flat, I'd be better off with the flat tire than the so-called spare!

[craigmar]

I would check the u-joints again also, nothing says that being brand new doesn't mean they can't be bad.

[skater]

I would check the u-joints again also, nothing says that being brand new doesn't mean they can't be bad.

True...how do I check them?

[lv2roam]

After doing the wheel alignment drill, replacing a bad rim, rotating tires, etc. Took the van to a drive train place. My drive shaft was out of balance - they checked out the unit for free.

So, take your van in to a drive line shop. They should eval for free and let you know if your problem is U-joint, drive shaft, or not.

[skater]

After doing the wheel alignment drill, replacing a bad rim, rotating tires, etc. Took the van to a drive train place. My drive shaft was out of balance - they checked out the unit for free.

So, take your van in to a drive line shop. They should eval for free and let you know if your problem is U-joint, drive shaft, or not.

Cool, thanks. I'm trying to think of any around here and none are coming to mind, but I'll have to look around.

[skater]

<Scotty>Cap'n, I dinnae think she can take any more!</Scotty>



I believe I may have found the problem!

Took the camper up to the dump station on I-95 today - but before I left I inflated the rear tires to 60-65 PSI (I couldn't get the one in the pic above about 62...I really need a better air compressor!). Anyway, the vibration was much better on the way up, and it didn't kick in until 55 mph. But the farther I went, the worse it got, and at slower speeds - by the time I got home, it was vibrating at 45 mph.

So, I pulled it in the driveway, walked around to the other side, and ... "Hey, what's that whistling sound?" (I've heard it plenty of times before, unfortunately, but it still gives me pause every time.) The air was leaking from the hole near the center of the picture, and as you can see the tire was pretty torn up - it was only a matter of time. I have NO idea how I didn't notice that damage before...maybe I didn't want to see it.

Fortunately it happened as I got home, so no real harm done. Glad it didn't happen on a trip or something.

I just ordered a new tire from Tirerack.com to replace that one. When it arrives, I'll take the spare rim off and have them mount the new one on the spare, then put that on where the flat one is. As for a spare tire... I'll order another matching tire later and put it on the spare wheel.

[skater]

Changed my mind - I put the spare on the camper and will put the new tire on the rim that has the blown-out tire. Much to my surprise, the spare is actually holding 40 psi - I've never touched it, never tried to inflate it. It's not safe to actually drive on, I think, since it's all dry-rotted, but it'll hold the camper up until I get the new tire mounted, balanced, and reinstalled.

The tire that blew has that type of damage in several places around the edge of the tread. Anyone know what this indicates? (Overloading? Heat failure? Age? etc.)

This thread has some interesting information (about halfway down, from CapriRacer) about testing the load on the tire. Inflate it to spec before starting on a trip, then measure it at 15 minute until the pressure stops increasing. It should only rise 3-5 psi; any more and the tire is overloaded/underinflated. Coolness!

What do you inflate your tires to? The sticker says 65 front, 80 rear IIRC, but really the camper should be weighed at a commercial scale to find out for certain.

[skater]

I bought a Master Flow MF-1050 after reading this and other articles about it (or another model just like it).

A couple notes:
1. It didn't seem to want to start against a heavy load - I blew two fuses before I figured out that it ran fine without a load but when I tried to start it against 60 PSI in the tire, it didn't do anything. I'm not sure if this was a break-in anomaly or if it'll happen all the time, but it's better to start it then hook it up. (It did start okay against 50 PSI later, so it may have just been a break-in quirk.)

2. The tire fill connector was pretty annoying, especially with my hubcaps, since it's hard to get my fingers in near the valve.

3. The pump ran quietly and although it took a few minutes, it was able to run the rear tire up to 80 PSI without a problem.

4. Between the cord and the hose, there's just enough length to get to the left rear tire from the camper battery. Not sure about the right rear tire, but it didn't look promising (though from the engine battery it'd be fine).

5. It includes a nice carrying bag and an extra fuse. It's actually a pretty decent compressor, it seems. Of course since I blew the two fuses that came with it, I'm now down to zero extra 30 amp fuses...but they're just standard automotive blade fuses that are available anywhere.

I'm going to think about doing what the guy in that link did - permanently mount it somewhere with a small air tank to give it a buffer. I also would like to replace the inflator nozzle, which means all new hose from the pump (due to the way it's set up - the hose and nozzle are one piece and they use a non-standard connection at the pump). It'd be nice to have a connection or two somewhere outside the camper, too.

[Alaskan]

Looks to have been run under inflated and got very hot...looks like its near ready to come completely apart... at freeway speed that could be an ugly experience

Run them at the recommended pressures front & rear, even if it seems to ride rough

We're very close to max on the rear weights per corner for the tires available to us, therefore you gotta run them at 80 or your gonna create heat which can easily result in a tire failure...

My 1991 weighs 5900# on the rear axle, divide that by 2 and you're right at the max for pretty much any Load Range E tire...

I use the Michelin XPS Ribs but they go on 9" wide wheels and have a weight cap of 3042# @ 80 PSI (load range E)

[ChasingRain]

looks like its near ready to come completely apart... at freeway speed that could be an ugly experience

I came very, very close to having that happen. Fortunately, the vibration got so bad I couldn't maintain highway speed. When I finally stopped, the tire was mostly bald, wavy, and had a few spots where the threads were showing. It was a scary experience.

When I put the spare on, it only had about 35 PSI in it- I need to remember to check it more often. Luckily, the exit ramp where I stopped was a few hundred yards from a gas station...

[skater]

Hopefully everyone else will learn from our lessons! Sounds like both of us got lucky.

I got the new tire yesterday, and I got it mounted, balanced and installed. I didn't take the camper for a test drive though, just ran out of energy.

I'm going to get another one and replace the left rear tire, and make what's currently there the spare. That tire is in fairly good shape, but the spare is completely dry-rotted, and a spare is nice to have. (Although I like the cleaner look with the spare off of my back door...)

[skater]

Success!

Got the new tire installed last night, so I took it for a drive tonight - had 'er up to 60+ mph several times with NO vibration! At one point I looked down and was surprised to see how fast I was going - way past the point where the vibrations started.

I blew another fuse (that would be #3) on the air compressor by trying to start it against 60 psi in the tire. D'oh. But it works fine if you start it then hook the hose up, so I'm not going to worry about it. (Also, I bet it is fine under most circumstances even at higher pressures.) I stopped and bought a pack of 30 amp fuses, and I put three in the bag with the compressor.

Now I'm ready to go camping again. I wish I'd realized earlier that I have a four day weekend over Memorial Day and had booked something - but it's going to be too late now. D'oh!

[Alaskan]

RJ..... keep in mind that mis-matched rear tires is not a good thing.

The possible difference in diameter of say a brand new tire and maybe a tire with significant mileage on the other makes the axles rotate and slightly different rates.....that can be very harmful or fatal to the gear assembly.

If you ran a tape measure around the circumference of a new tire and a used tire it will differ....not what you want to run on the rear

On the front it doesn't have that affect and is much less important, although it can make the rig pull one direction or the other...

Replace your tires in pairs at least...