Community Forums

Myron · 05-10-2006, 08:35 AM

I have a 2005 8.1 . The brakes have been worked on so there may be something associated with the hydroboost.
My question or problem is that when accelerating hard or climbing a hill a whining noise like a pump building pressure comes from the engine compartment. As I reach speed or level off on the accelerator you can hear the pump build up pressure and shut off.
The brake issue was hard pedal. They replaced the hydroboost unit I believe. The brakes are still inadequate for this weight as far as I'm concerned. I guess this is the best it will get. The whining noise is concerning me . It did not do this in the beginning.

Myron · 05-10-2006, 08:35 AM

I have a 2005 8.1 . The brakes have been worked on so there may be something associated with the hydroboost.
My question or problem is that when accelerating hard or climbing a hill a whining noise like a pump building pressure comes from the engine compartment. As I reach speed or level off on the accelerator you can hear the pump build up pressure and shut off.
The brake issue was hard pedal. They replaced the hydroboost unit I believe. The brakes are still inadequate for this weight as far as I'm concerned. I guess this is the best it will get. The whining noise is concerning me . It did not do this in the beginning.

Eagles Nest · 05-10-2006, 09:50 AM

Hello;
My good friend has a 2006 Workhorse, and was making I think the same noise. In his case it was the power steering pump! The whine, is still there but not as loud. Hope this helps.

Myron · 05-10-2006, 11:18 AM

The power steering pump is part of the braking system so perhaps the real problem with my braking is a power steering pump. I have suspected it for a while. With the engine off, front tires off the ground, turning the steering wheel clock to clock makes the power steering fluid reservoir overflow. I suspect a check valve is causing the issue. Maybe I have more ammunition now. Thanks.

DriVer · 05-10-2006, 12:38 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Myron:
The power steering pump is part of the braking system so perhaps the real problem with my braking is a power steering pump. </div></BLOCKQUOTE>Yes we have seen this unit at times present trouble however the fix is pretty straight forward. Like you suggested a check valve seems to be the problem.

I am surprised that the pump wasn't considered problematic when they changed out the Hydro-Max.

Yomo · 05-14-2006, 08:27 PM

Are you sure it is not the fans kicking on? At least that is what I think is going on with my coach. Mine also whines, but then stops.

Myron · 05-17-2006, 08:32 PM

I am sure it is not the fans. They don't sound like a pump building pressure then shut off when the pressure is built. It is related to the throttle position usage. A gentle acceleration will not cause the whine. A floored accelerator will make it whine and I can let off the accelerator and the pump seems to stop quicker.

Myron · 05-17-2006, 08:34 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Myron:
The power steering pump is part of the braking system so perhaps the real problem with my braking is a power steering pump. </div></BLOCKQUOTE>Yes we have seen this unit at times present trouble however the fix is pretty straight forward. Like you suggested a check valve seems to be the problem.

Does this check valve create a poor braking problem ? And this check valve would be located on the power steering pump ? Is it an external check valve or does the steering pump need to be replaced ?

I am surprised that the pump wasn't considered problematic when they changed out the Hydro-Max. </div></BLOCKQUOTE>

DriVer · 05-18-2006, 03:42 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Myron:
Does this check valve create a poor braking problem ? And this check valve would be located on the power steering pump ? Is it an external check valve or does the steering pump need to be replaced? </div></BLOCKQUOTE>The sound that you are hearing doesn't make for poor braking action. It would be best for you to bring this matter to the attention of a service center and have them evaluate the condition that's creating the noise.

Tom&Marie · 07-20-2006, 07:01 PM

I think I have experienced the same sound you are referring to..I have 6500 miles on my MH and it started recently on a trip from West Palm to Augusta...Was at WH yesterday and the noise was determined to be a faulty a/c compressor..tech heard the noise during road test and while accelerating turned off the a/c noise stopped...

rickandcheryl · 07-21-2006, 06:35 AM

Check to make sure the engine fan is not rubbing the fan shroud. If it is, it makes the sound you have described

WinnebagoDRVR · 08-13-2006, 09:46 AM

Hey, what was the final word on this noise?

Mine started doing it after they worked on my parking brake last month.

Under high RPM's/acceleration you can definitely hear a high pitched pump pressurizing something, and then a few moments after the rpm's are reduced it shuts down...

wilanddij · 08-13-2006, 10:44 AM

Tom&Marie,
I have the same symptoms, but its not a whine, its more of a high pressure air "hissing" noise. Mine just started doing it somewhere around 7500 miles. It stops when I turn off the AC, or the trans shift into 5th. A couple of folks have suggested a vacuum line, but I don't see any vacuum hoses coming off the intake manifold. Please let us know if the AC compressor replacement fixes your problem.