jdgreen42
Silsbee, TX 77656
Senior Member
Joined: 05/01/2004
View Profile
Good Sam RV Club
|
Do you have vacumn assist power brakes ? Sounds like a vacum leak to me.
Don
|
1995brave
San Antonio, TX
Senior Member
Joined: 01/24/2006
View Profile
 Offline
|
Find the vacuum assist motor and check it out. It could be dry bearing or sleeves on the motor and it just needs oiled or greased. Get it checked now before the motor freezes up and you have no vacuum assist.
|
50pascals
rochester, ny
Senior Member
Joined: 01/10/2008
View Profile
|
So guys are these vacuum assist or electric assist?
If electric, has anyone given any thought to the idea that the motor may have a bad bearing?
I don't know the chassis specifically, but I am guessing by your posts that he does not have Hydromax brakes (powered by power steering pump).
|
RayChez
Barstow, Ca. USA
Senior Member
Joined: 09/13/2003
View Profile
|
Gale Hawkins wrote:RayChez wrote:But when that electric motor comes on it is not a squeal like he discribes it. The five ton Ford truck that I drove every once in a while had electric over hydraulic brakes on it, but what it sounded to me was like when you turn on the electric water pump on the coach. It was not a squeal.
A squeal to me would be glazed brake shoes or worn brake shoes. The only thing that throws me a curve is that the OP mentions that the sound was under the dash. That would put it right around where the electric motor is for the brakes.
Ray what about the info that it does when parked too. 
Electric over hydraulic will do that. The harder you press on the brakes the faster that electric motor will sound. What it means is that you are having a hydraulic failure and the electric motor is trying to help. If the brakes are working properly this electric motor shoudn't even come on. The Ford 6000 that I used to drive every once in a while I took it for service and instead of adding brake fluid to the system, they added atf. Driving down CajonPass, Ca I pressed on the brakes and the pedal started going down and that electric motor come on right away to help me stop this five ton truck. If the OP has electric over hydraulic it might be that motor that is making the sound. I know that Fords used to have that system. I am not sure what the RVer in the original post has.
|
jeepfreak
Hanover Ma.
Senior Member
Joined: 09/02/2002
View Profile
Good Sam RV Club
Offline
|
Sounds like it could be a fan belt. Could be slipping under the load of the power steering pump which powers the hydroboost brakes.
2007 Allegro 34wa Workhorse 8.1, Allison 6-speed. Bow Tie powered 79 CJ-7 TOAD ,when A/C IS needed 2000 Grand Cherokee Toad
|
|
|
50pascals
rochester, ny
Senior Member
Joined: 01/10/2008
View Profile
|
jeepfreak wrote:Sounds like it could be a fan belt. Could be slipping under the load of the power steering pump which powers the hydroboost brakes.
I like your thinking on this one!
But just to point out, if they are Hydromax, there is no vacuum assist.
|
50pascals
rochester, ny
Senior Member
Joined: 01/10/2008
View Profile
|
dup post
|
randallb
On the road
Senior Member
Joined: 11/19/2007
View Profile
Offline
|
ww,
Get it checked out. You now have an argument going over how this vehicle may be equipped. You have not joined back in with further explanations of the system so that leads me to believe you do not know. Do not rely on any forum for a diagnosis of a potential brake problem.
|
AspiringJAG
Palm Coast, Florida
Full Member
Joined: 04/20/2008
View Profile
Good Sam RV Club
Offline
|
might be "outside the box" here... but it sounds to me like it could be your trailer brake control unit (assuming you have one)...
30ft FourWinns Class A w/ chevy 454, VW Jetta on a tow master dolly w/brakes, wife, 3 kids,& Basset Hound,
|
mkriedel78
Halethorpe, MD
Full Member
Joined: 02/09/2009
View Profile
Good Sam RV Club
Offline
|
Well, the OP may not have replied, but this thread piqued my interests- especially after today. My 2000 Itasca is on a F53 chassis, and I noticed that it was making a similar noise to the OP's. Slightly different scenario, though. Mine occurs when the engine is running, and is definitely not the electric motor (I've heard that before and it's totally different).
I hear a high-pitched whistle, almost like air is being leaked out. The harder I press the brake, the higher pitched it gets. And it's definitely under the dash.. My first thought was vacuum booster as well.
Assuming that's the case- what am I looking at (in either cost or level of difficulty) to get it fixed? I would rate myself as an "adequate" mechanic (can do oil, basic run of the mill stuff).
Thanks,
Matt
|
|
|
