Master Brake Cylinder

Thank so much for all your comments....My husband will take from here....I feel so much more prepared to deal with the mechanic in the morning. I will be able to know the right thing will be done. I had new front brakes and reservoir installed 5 months ago and reinspected before our trip. Our local service dealer said all was good. So, I will use all your thoughtful suggestions and hopefully have this resolved, so we can be home for Thanksgiving. Thanks to all again.

Monterey Bay Cruzers wrote:
... since the brakes seemed fine on our 5 mile trip to the RV park... (were the brakes just hot from the stop and go traffic?) Should we continue on our way home? Our RV is a 1998 Fleetwood Pace Arrow. We only have 23,000 on it.

When was the last time you have the brake fluid flushed? This does sound exactly like a moisture in the brake fluid problem... Both of your symptoms (fluid leaking from the master cylinder, soft brakes) match, and as well the fact the brakes worked OK after cooling is another flag that you may need a brake fluid flush.

I will add that to my list. Thanks so much!

i too think it is the Master Cylinder

hot brakes normally occur with heavy braking, like going down hill

stop and go on fairly level normal terrain, will not cause hot brakes

its the rolling resistance trying to control speed that heats up the brakes

unless of course someone is riding the brake pedal in slow traffic

a stuck caliper in stop and go traffic, might contribute to heat and brake fade

There is no way your going to get the brakes that hot in stop and go traffic.

Be interested to know the mechanics observations. When I bought my motorhome a decade ago the brakes were soft. I filled up the master cylinder and drove it home. I bought a rebuilt master cylinder from Advance and replaced it myself. It worked perfectly after that. It was a bull to get too. Thank goodness for air wrenches.

Monterey Bay Cruzers wrote:
We were on our way home yesterday after a glorious trip to the Grand Canyon, Sedona and Palm Springs. We were in stop and go traffic on 101 for about an hour. Suddenly, my husband said the brakes "went soft". Luckily, he got off the freeway and we sat on the side of a very wide off ramp. We were towed to a parking lot. We called a Good Sam suggested roadside mechanic. He said brake fluid was normal in brake reservoir even tho fluid was dripping from the reservoir. All of this took a couple of hours. After testing the brakes in the parking lot, the mechanic felt we were safe to go to a nearby RV park. We're not sure whether to stay here and wait until tomorrow to have a mechanic look at it or since the brakes seemed fine on our 5 mile trip to the RV park... (were the brakes just hot from the stop and go traffic?) Should we continue on our way home? Our RV is a 1998 Fleetwood Pace Arrow. We only have 23,000 on it.

Sounds like you boiled the brake fluid.
This usually happens with improperly descending a steep grade.
It can also happen with driving in heavy traffic, if the brake lines are close to the exhaust manifold.
The immediate cure is to flush and replace the fluid and do so again in two or three years.
New fluid has a boiling point of 400F +, but with time, it collects moister and yours most likely will now boil at 212F.
On our old gas coach, I put a piece of alum. between the brake lines and the exhaust manifold to better direct the air flow and for blocking the heat, somewhat.

as I said in first post sounds more like master cylinder bypassing
once fluids are boiled and theres air in the system the pedal stays soft till bleed out;; in this case the pedal returned to hard normal
at least what OP indicates

Should we continue on our way home? Our RV is a 1998 Fleetwood Pace Arrow.

IMHO. No.


FRONT BRAKE LINES

I lost my brakes coming off an exit ramp just like you did! Everything checked out ok. Thank god I had an experienced truck mechanic at the repair shop I limped into.

You can NOT tell when the front rubber brake lines go, they will look perfectly fine on the 'outside' no leaks or cracks...BUT....

The rubber deteriorate on the INSIDE. They collapse inside and cuts off the brake fluid. And it can be intermittent but all it takes is that one time that they collapse and you have a serious accident.

He took the front brake lines off and replaced them. Problem solved. It is a 'VERY' common problem on 1996 to 1999. But can happen to any year.

The fact that your 98 MH only has 23,000 miles on it means it has sat parked some where for a long time. Brake lines should have been the first thing you replaced and the second thing that should have been replaced where the master cylinders because of accumulation of rust while sitting.

We ended up staying two extra nights and met with the mechanic the RV park owner recommended. We were there the first thing this morning. Luckily he was able to fit us in and replace the Master Brake Cylinder. He evaluated the symptoms that I explained and knew what needed to be done. I was keeping in mind all that was posted here and it was very helpful. Thanks again.