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Hi all,

I was hoping for some suggestions after my bus decided to be finicky just as I need her the most.

First, 2 bolts broke on my pass. side CV joint at the wheel. The other bolts backed off and the joint fell off. I got under and retightened it and it would happen again after awhile.

Around this time, the engine started making a fast knocking noise after it got warmed up. It starts when I come to a complete stop and is noticeable on acceleration and deceleration...

If I put my finger on the carb to rev it up, I can feel the knocking vibrations.

I don't know where to start...

Engine specs:
1600 SP was built from all new parts by a very reputable VW shop just over a year ago. Has about 10k miles on it. Recently tuned. Driven gently, using 91 gas.

I've had the same problem with CV joints but it was on the tranny side. I ended up replacing the axle flange on each side and installed all new hardware after having the axles serviced.

Are you sure the knocking is coming from you're engine? CV joints knock when they need attention. You didn't say if you fixed the CV joint problem and then the knocking started or did the bolts come loose and then the knocking started? You might want to pack some grease in the CV joing and see if that helps. Hard to say what a sound is without hearing it for yourself.

Good luck,
Brent

I think you are looking at two separate problems...that just unfortunately co-incided. The CV joint coming loose could either be from not having the correct locking washers under the bolts...or a bent hub. The knocking you feel could be coming from the clutch or flywheel area...orsomewhere in the tranny while in neutral. I would run a compression test and then adjust teh valves to start ruling things out. It would be worth it to crawl under and feel teh transmission to see if the knocking is coming from that. Ray

Hiya SB71,

I'm throwing in with Ray on this one. Definitely sounds like two seperate problems.

On the CVs......... Upon installation each of the bolts should be torqued to 25 ft/lbs. They have been known to work their way loose after an installation, so it is always a good idea to retorque these bolts a few hundred miles after the first time. I always do this and have never had a CV joint loosen up on me (but my fingers are crossed).

And obviously, if you have your have finger on the carb and feel this knocking noise, your CVs are not turning. Either that or you can run really fast in a very awkward position. I'd agree with Ray and run that compression test. But to tell the truth, knocking sounds are just not good news. Hope for the best, but be prepared for the worst.

Mike

1970 Bus - The Ruptured Duck

How many miles on this motor? If 100k or more, I'd be worried about a rod knock. This is when the piston connecting rod is worn out on the crankshaft and moves a bit, causing a low knocking sound, worse on deceleration and idle, goes away with higher revs. Just a thought.

Satchmo

Thanks guys,
I'm going to go adjust the valves here in a minute to rule that out.
Yea, I have 4 of 6 bolts in the CV right now because two have studs broke off in them and I don't have a drill right now.

The engine has 10k on it, and the transmission is rebuilt from Rancho Performance and has about 8k on it.

I'll post my findings this afternoon after some investigation.

Dis just the heads break off? If so...just remove the inboard and outboard end together and pull the joint off the bolts and remove them with vicegrips. If they broke off flush inside the flange...just get a stub axle from the junkyard. Trust me...you will end up with wallowed out holes...casuing problems. These bolts are extremely hard. drilling is not really a good option. Ray

OK,

I found the source of the knocking...The #1 intake rocker retainer clip broke and I lost the wave washer too. The rocker has about 1 inch of sideways play and the knocking was it smacking the valve spring. Ouch!

Note to everyone: when building your engine, don't ignore the valve train for worn components...

About the CV:
I know it may not be the best option, but I'm gonna try drilling as soon as I get a drill, because I need the bus on the road...Does the axle stub require removing everything on the wheel?

I really wish this wasn't happening, but such is the nature of driving a 33 year old loaf.

The stub axle is really not very hard. It will certainly take less time than drilling out the bolts. They are very very hard. Perhaps the hardest bolts on the whole vehicle. They are harder by a good deal..than grade 10.5 if they are original stock. So if they are not broken off down inside the actual axle flange...they will take maybe 10 minutes with vice grips once you take the whole axle out. Ray

They're broke off clean, no vice grips here. <sigh>