Help me diagnose my wierd noise

Could be bad motor mount, backing up and then moving forward loading the axle on one side perhaps. I would jack the back up and support chassis with jack stands and then place jack with a pice of wood or shop rag so as not to dig up motor. As you lift the engine a small amount you would see the bonding separate at the mount. I had the front tranny mount seep rat and this is how I found it.

 

I would also rotate the wheels and check the axles for any strange behavior while it's on the stands. Bad joints will also aggregate noises in the transition from reverse to  froward and settle out as you continue forward.

 

If you're feeling it under your but it is somewhere under the car.

 

 

Could be mounts.....   Best recommendation is to get it up on a lift and go over everything you can see or reach....   Don't know what else to tell you...  

 

Agree...most likely mount(s)

Jack, I'm far from an expert here, but I developed a chatter in the clutch that got worse over time. It was ok after the initial launch and I could avoid it if I reved the engine a little when I took off, and all the other gears were ok.I thought that it was a worn out clutch and since I was leaking a bit from that area I thought that the leaking was contributing to my chatter. After looking at the clutch plate I saw that it was glazed a bit, but not a great deal of oil was found there when I removed the engine for a rebuild. The front and rear tranny mounts, however, were hammered to death. I didn't realize how much difference it would make until I replaced them and had the new engine in. Handling and steering were hugely better and starts in first gear were smooth. I don't know what made the difference, but I was told by people who are expert (Danny Pip among them) that I would notice a big difference in handling, and I did. Bad news is that the engine has to come out to get to the rear mounts. The front mount you can see and I replaced mine without removing the trans.  I hope it's easier than that for you because your engine is beyond fine.

 

As I said , I'm not an expert here but the guys above this are.  Happy motoring and good luck brother.

 

Adding to what Mike mentioned up above, if it's motor mounts then get it p on a lift, grab the J-pipes or the exhaust pipes - whatever is grazable towards the outsides of the engine (left/right) and try to rock the engine.  If the mounts are bad it'll rock quite a bit and you'll be able to see the mounts flexing.

 

I'm a little puzzled about the backing up and taking off groan thing, though.  It certainly could be the mounts shifting, but it might be brake related, too, like a caliper that's not letting go enough and is dry and sticking.  That's always good for a low-pitched noise just as you're taking off.  

 

Either way, the way to find out what's going on is to get it on a lift and get up under there and poke around.  If it's the mounts you'll see 'em, and if it's the caliper/rotor then the wheel will be harder to turn on that side.

This is probably way out in left field, but in a type 1 a noise similar to what you describe can mean a loose flywheel (and you wonder how a gland nut torqued to 3 or 400lbs could come loose, but they occasionally do), so while you have the engine out to replace mounts, check that the flywheel is tight and spin the throwout bearing to make sure it's not making noise. I'm of the understanding that type 4's don't have this problem, and as has been mentioned it's probably the mounts, but it doesn't hurt to check....Al

Jack - don't back up!

Al, I hope Jack doesn't have a loose flywheel! I really don't think that's possible, with 5 bolts and Jake probably torqueing and loctiting it up!

 

Motor mounts or brakes, or possibly a wheel bearing thing. A shifting(worn) motor mount could be allowing something to slightly rub somewhere is most likely.

A loose flywheel is unique - something that sounds like you're grinding up walnuts back in the engine area.  Once you've heard it (especially for a couple of weeks while you're trying to figure out what the hell it is) you never forget it.

 

I had a flywheel loosen several times on a dune buggy I built.  Torqued it to spec a couple of times and still, it got loose.  The last time I welded two opposing flats on the gland nut to the flywheel and ran it for a couple more years til I sold it and the NO ran it for another three years.  All is not lost......

This sounds like the rear brake issue someone else had a while back.  For some reason, I feel like I had a car that had this feature. I just can't remember if it was  VW or another make. Effectively the drum shoes would 'self adjust' to the proper tension / spacing every time you backed up (some relied on the e-brake).

 

Maybe it was my TypeIII that had this option?... I forget. But when I read the first post in this thread I thought - sounds like brakes to me...

 

Jack - what are you running for rear brakes? Drum or Disk?

 

Maybe I'm wrong - but let's rule out the simple stuff.

 

Issue solved---as TRP said, it was  a brake issue-----sort of.  The sound was caused by separation on the two pieces of the left rear disc brake  hub.  There is a  small steel inner part that goes onto the splines and a larger outer aluminum hub part that is press fitted to the inner part and the two pieces comprise the hub.  Jim Ignacio warned me 5 years ago that this might happen.

 

The mfg said that yes, it could happen but only if the wheel nuts were not torqued to spec which mine were.  I even bought a giant torque wrench to easily provide the 220 ft pounds spec'd.  In addition to the torque set at installatioin the torque must be checked once or twice a few weeks apart which I did myself. 

In my case the inner part was spinning inside the outer part making the noise but going forward iot gripped and worked as normal.  It was only going from reverse to forward that the groan sound was there and the sense that something was shifting around.

 

Kudos to C. B. Performance because even after 5 years of use they are giving me a big discount on the replacement hub that arrives here tomorrow.  Now that's standing behind your product like you rarely see.

 

I am so fortunate to have a sensational imported car repair service right here in Dogpatch and they diagnosed it quickly and will replace that hub at a reasonable charge tomorrow.

 

I appreciated all the suggestions posted by SOC'ers here  and want to say thanks.  Now we have one more solved issue that might help someone else in the future. 

Congrats Jack!  So happy it's not something worse.  Natalie should be back in my garage this morning.  See you @ Corn Daze.

I hope CB solved this issue, it seemed to happen often a while back and I believe Cory had this problem with his rear brakes years ago.

 

Glad you found out the problem, Jack. It is good customer service from CB but I'm almost thinking this is an expected probability with these rear brakes, hence the partial refund.

Way to go Jack......   

Jim "Nostradamus" Ignacio strikes again. 

 

Nicely done, Jack. Not so serious after all is a good thing.

Glad it was an easy fix, Jack! Now full speed ahead to Corn Daze Trois!

 

Musbjim aka: Guamstradamus 

Jack, I believe the 220 pound torque rating is for the hub nut.  Could the person have been talking about the lug bolts on the wheel?  That should be around 80 lb ft, but many places don't check.  They just use an air wrench at whatever setting and run 'em down.

Way ta go, Jack!  Always nice when the solution presents itself.

 

Is this your local "Import Service" in Dogpatch?

 

Guamstradamus---priceless.

 

Funny as hell photo, Gordon.  I'd really have to be in a bind to use a place like that!  Our import place is totally professional and smart on any car.  They get the scvoop that is in question off the internet and know where to find the right parts.  I trust them 100%.

 

Lane--yes 72 ft lbs on lug bolts is the official VW Type I spec.  The VW spec is 220 ft lbs for the Rear axle nut but the directions for the C.B. Perfoemance kit say 250ft lbs.    I guess we'll go with the 250 and maybe that's to hold it all together.  Or split the difference and go 235?

My point was that it seems more logical to me that the lug bolts could cause warping or separation of the rotor.  We had that problem repeatedly with a T-Bird Pam used to have.

It wasn't the roor , it was the hub.  Tried to post a picture but failed.

Jack:  torque the hub nuts to 250+ ft lbs.

 

gn

What accuracy +/_ range is acceptable for a torque wrench?