Brake master cylinder replaced, now engine has high pitched whine

micd · 12-05-2012, 09:00 AM

Hello everyone, why is it when you get some work done on your RV it comes back damaged or dirty? That was a rhetorical question. So here is my real question.

We just had the brake master cylinder replaced on our RV. When we picked it up it had a high pitched whine coming from the engine into the cab but you couldn't hear it outside(likely because the engine noise covered it). It is present when the engine is on and does not seem to vary with the engine speed although at one point while accelerating it did seem to go away but that only happened once on the way to the storage lot.

I called the shop this morning to see if anything had been removed like belts etc. when they did the brake master cylinder. And they said nothing but the dog house had been taken off. They charged us for 6 hrs labor and I suspect we were taken advantage of so I don't know how good of a shop they are. This is the first time we used them. Total cost with parts and labor was $530. Based on my research this should have been a $350 job but since we had the RV towed there I let them do the work even though they refused to provide an estimate up front.

Any ideas of what we should be looking for with our mysterious new high pitched whine?

John Hilley · 12-05-2012, 09:27 AM

Maybe it has to do with how they reseated the doghouse. Labor does seem high. What was their hourly rate?

Davel · 12-05-2012, 10:52 AM

Micd,

A vacuum leak would go away under acceleration....

Dave

rsflight · 12-05-2012, 11:24 AM

I suspect that you have a hydraulic brake booster that provides the power brake assist. Sometimes they are disconnected to do the brake work allowing air into the boost hydraulics, thus creating a whining sound. Check the hydro-boost fluid level to be sure it is within spec, pump the brakes very hard several times with the engine off to cause the auxilary pump to cycle on & off then turn the engine on and repeat the process. If needed repeat the process several times. These steps usually get the air out of the system quicker than just driving it.

micd · 12-05-2012, 11:34 AM

Thanks for the input. We will try your method rsflight. Any idea where we would look to check the hydro-boost fluid level on a 1994 Winnebago Brave 454 chevy engine, P-30 chassis?

The labor rate was 76/hr and they said they logged 6 hours on it. The hourly rate is reasonable but 6 hrs seems long for this type of repair.

Thanks to everyone for the suggestions! We will have to go visit it this weekend so we diagnose in daylight.

garykk · 12-05-2012, 11:40 AM

Don't know where you had the work done but many states require a written estimate before any work is done and no extra work unless verified with the owner, all removed parts must be saved for the owner.....6 hours is a bit much...

micd · 12-05-2012, 11:47 AM

Yeah, I know. Their website says free estimates but when I talked to them after they diagnosed the problem they wouldn't give an estimate. To take it somewhere else I would have to tow it again and I figured how bad could it be. But I now know how they are so will go elsewhere in the future.

My engine usually sounds like such a honey that hearing it not sound right is very concerning. I'm surprised they didn't notice it.