TheSamba.com :: View topic - HELP! HELP! ...Mystery "Noise" in my 71 Baywindow

Fri Nov 21, 2008 12:25 pm

HELP!!
I have a 71 Bus that I bought about six months ago. I just had a rebuilt stock dual port and rebuilt trans installed. My issue is a "noise" that has developed. It is coming from the rear of the vehicle. It is the most prononnced when you are going between 5 and 30 mph and slowing. An example in coming off a freeway offramp in 4th gear with no accelerator imput. When I put the car in neutral and freewheel it is very noticeable. When I put in the clutch (still in neutral) in gets a little louder. As I slow to a stop the noise goes away at about ten milles per hour. There is no noise at idle. Applying the brakes when moving has no effect on the noise. I would describe the noise as a "metallic high pitch rubbing noise" similar to a Brake noise when pad is wearing out.

The mechanic took the car back to the transmission builder who drove the car and said it was a "rotation" noise and not worth "chasing". He went on to say that it was a product of a 37 year old bus. I have had several buses over the years and have not experienced this situation. It does concern me.

QUESTION:
1) Has anyone out there encountered a similar situation?
2) Can anyone refer me to a miracle mechanic in the South Orange County, Cal area (I live in San Clemente) who might be able to diagnose the problem?

I appreciate any input....Thanks....Rick

Fri Nov 21, 2008 12:47 pm

I would say lift both rear wheels off the ground and take a listen. You have a lot moving at the same time back there. Could be CV joints, clutch, wheel bearing or trans. Kind of hard to rule one out unless you listen close with a stethoscope.

Fri Nov 21, 2008 12:51 pm

Without hearing it in person it's difficult to diagnose noises, your's seems like a pilot bearing or input shaft bearing. You need to try harder to hear it sitting still with the trans in gear and the clutch in as well as in neutral with the clutch out, one of those will narrow it down.

Fri Nov 21, 2008 12:54 pm

Thanks for your response...WE did jack up the rear of the car and run it at moderate RPM. The noise was not there. I am having the mechanic replace the rear wheel bearings and check the CVC at the same time. I have no real confidence that this will cure the noise , but I guess I will have peace of mind that those systems are a "go"!!

Fri Nov 21, 2008 12:56 pm

Busdaddy,
The problem is is that there IS NO noise when the bus is sitting still (or even when rolling less than 10 mph)....A real head scratcher!!

Fri Nov 21, 2008 12:57 pm

Lift the rear up and put it into gear and rev it up over 10.

Fri Nov 21, 2008 1:00 pm

Brett,
I did lift the rear and run it in gear to probably 25 mph....no sound?...really confusing because the noise in definitely loud enough to hear when you are on the road!!

Fri Nov 21, 2008 1:07 pm

Well it sounds like some type of load issue then. Acceleration or deceleration. Which still could be trans, cv, or wheel bearings. If you are stationary and apply the clutch and it does not make a sound I think you could eliminate the throw bearing. Try that in and out a couple of times.

Fri Nov 21, 2008 1:10 pm

Just out of curiosity did you touch anything else or did you have this problem before the rebuild. You could have replaced the cv joints in a different arrangement. Like different side or correct side but reversed. You may have changed the area on which the ball bearings are running and they are running rough.

Fri Nov 21, 2008 1:27 pm

Brett,
I just talked to the mechanic and he is going to check and see if the cvc's
are reversed. He doesn't think that the sound is cvc related, but we wll see....thanks...Rick

Fri Nov 21, 2008 1:33 pm

It shouldn't matter if they are good but they do wear in one spot if they have been in for a while.

Fri Nov 21, 2008 1:36 pm

Suggestion:

If it has not already been done under your ownership, change out the transaxle fluid with fresh and have the CV joints inspected/repacked with nice fresh CV joint grease.

See if that changes the noise.

Repeat every 30,000 miles.

Fri Nov 21, 2008 1:43 pm

Rick,

We have a master mechanic stopping by for yet another test drive this afternoon.

Will call you with the results.

Fri Nov 21, 2008 2:45 pm

Randy,
The trans is new, but I planned to change the fluid at 1000 miles. It was filled (and still is with G-4). I am having the CVC's serviced as we speak....Thanks for the info....Rick

Fri Nov 21, 2008 3:00 pm

Your guy will figure this out. Tell us what it was though.

Fri Nov 21, 2008 3:05 pm

Randy,
When I solve this mystery I will ad it to this thread....Hopefully it will help someone else in the future....Thanks....Rick

Fri Nov 21, 2008 3:39 pm

Front wheel drive cv's are easier to diagnose. You do a tight turn forwards and backwards in both directions and they make crunching sounds like crazy.

Fri Nov 21, 2008 4:46 pm

Brett,
The sound is more of a metal "rub" (like worn out brakes). It doesn't seem to matter how the car is steered.....definitely in the rear though.
It will be interesting if anyone responds over the weekend with a similar experience.....Thanks....Rick

Sat Nov 22, 2008 4:38 am

My 70 used to do this noise thing found out shoe dust accumilated in drum caucing noise. I drilled a hole in each drum so dust could get out,it happened on a reguliar basis but holes ended it . Have to get right angle of holes in area where shoe rub stops on drum and in corner of drum, no more problem ,i used 1/4 bit.

Sat Nov 22, 2008 7:33 am

morymob wrote: My 70 used to do this noise thing found out shoe dust accumulate in drum causing noise. I drilled a hole in each drum so dust could get out,it happened on a regular basis but holes ended it . Have to get right angle of holes in area where shoe rub stops on drum and in corner of drum, no more problem ,i used 1/4 bit.

Rich might of noticed this when he had the back end off the ground and did some investigating. If everything was ok before it has to be a trans problem. Like the cv joint rubbing on the trans housing. Bad output shaft to cv joint bearings maybe. Some type of torque related thing that is not present when you lift the rear end up.