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-   -   Dragging Brakes getting HOT (https://www.irv2.com/forums/f23/dragging-brakes-getting-hot-539610.html)

eastkytriker 06-03-2021 04:07 AM

Dragging Brakes getting HOT
 
2005 Winnebago class c Ford E 450. Changed brake pads and rotors and started getting ready for first trip and the brakes are sticking all four wheels at the same time. calipers are good and slides are working good. Thanks in advance for any help possible

andy29847 06-03-2021 04:38 AM

I would bleed all the calipers. When doing this, I would use enough brake fluid to insure all the fluid in the system is new.

Old brake fluid can lead to corrosion in the system which can cause sticking brakes, usually at the calipers. Sticking calipers normally shoes up on just one wheel at first.

A bad master cylinder can cause this to. You'll most likely see the effects of this on the front brakes (hot) reduced gas mileage, and feeling of low power.

TeJay 06-03-2021 07:26 AM

The age of the MH tells me a lot. Are you the original owner? If not then you don't know if any service was done to the calipers.

The square cut rubber around the piston calipers is what pulls the piston back from tge pads when pressure is released from the brake pedal. The way that works is simple. When the brakes are applied the square cut rubber ring/seal distorts allowing the piston to put pressure on the pads. When the pedal is released the seal returns to its original square cut shape pulling the piston away from the pads allowing about .010 of space between the spinning rotor and pads. When that square cut seal looses its ability to return to its original shape the piston sticks causing more rubbing and therefore more heat.

If those seals have not been changed since it was new in 2004 the calipers need either replaced or rebuilt.

The only strange thing is you say its happening to all four wheels. Then I'd head in the direction of the brake system never being flushed and therefore a lot of dirt will be in the system perhps plugging up ports keeping the fluid from returning to the master cylinder (MC).

The best advice you got was to flush the brake system. Buy some speed bleders and install them at each caliper. It's a brake bleeder with a check valve. That allow you to bleed the system by your self and completely flush all the lines as well as everything else in the system. That just might get your blockages removed.

There a few threads on the use of those speed bleeders. Summit racing has a good selection of thse valves. They remain on the calipers so one can bleed the system about every 3-4 years. I just did our again and after 3 years the fluid was again fairly dirty and for sure had some water in it as well.

Last point. After 40+ years working on vehicles of all sorts I've only seen one system that had a blocked proportional valve. Tha was cause by the rubber lines that had deteriorated over time and the tiny rubber particles were all through the system blocking up ports. Since you may or may not know the RV's history I'd guess those flexible lines are stock and should be replaced while you're doing all this flushing.

You have an RV that is 17 years old so it needs some serious brake service.

HarryStone 06-03-2021 09:41 AM

While not cheap, https://www.amazon.com/Motive-Produc...07457373&psc=1
is what I use to bleed brakes. I modified it by installing a metal tire Schrader valve, so I could use air pressure instead of hand pumping it up. Once hooked up, and filled with brake fluid, you just need to go to the tire and loosen the bleed valve with a tube on it and a bottle, and it will push fluid until you close the valve.

Skip426 06-03-2021 10:03 AM

How far has the coach been driven since the brake work ?

If you park on a slight incline , with the coach in neutral , will the coach roll at all , or does it remain stationary ?

You need to be sure the brakes are actually sticking !

Because , new brake rotors are shipped with an " anti-corrosion" coating ; installers will clean the coating from the pad running surface ; BUT ; there is still the coating in the rotor cooling fins that takes miles and multiple applications to burn off and dissipate .

wolfe10 06-03-2021 10:07 AM

All 4 brake positions failing/not releasing at the same time points me to either having sat a REALLY long time or a problem with the master cylinder or brake pedal not releasing.

TeJay 06-03-2021 11:36 AM

If the calipers are sticking it's for one of two reasons. The caliper pistons are sticking due to the square cut seal. If that's OK then fluid is not bleeding back through the system either at the wheels, the proportional valve or the MC.

You could drive it just 1/4 of a mile and after a slight application of the brakes if they don't release then they will be hot to the touch.

I've done enough of this stuff to know this. I don't know who did the recent work but there's no guarantee that it was done correctly. Here's what I'd do.

Determine if all wheels get hot. If they do get hot then I'd speed bleed all the fluid from the system. Drain it wheel by wheel until all the fluid is clean. Then drive it again. If what ever was not allowing the fluid pressure to release you'll know because the brakes will be working.
Open a bleeder screw at a hot wheel and see if fluid comes out indicating some pressure is not bleeding out of that wheel. I've actually seen a collapsed rubber flexible hose. They collapse internally and not allow the pressure to release. You can see the bulge not release. If your rubber flexible hoses have not been changed that can and will cause what you're having.

Yes brakes will always get hot when they are used. When they don't release properly they will get smoking hot and really fast. They are designed to create friction to stop the RV. If they are not releasing you'll know that as well. Either the vehicle will pull to one side if it's on the front or one or more wheel will be very, very hot.

If that's what you find then rebuild the calipers. You may have more than one issue so solve what you can determine is defective by following the symptoms. Never assume because something is new or recently repaired that is has not failed again.And never, never skip a test that can determine what is causing the problem.

You can't name me a part on any mechanical/electrical system that can't be tested to determine if it is doing the job it was designed to do. When it's tested it either passes or fail and it will show a symptom when it fails. Fix the cause of the symptom only after you've ckecked each part to determine if it's functioning as intended.

Many times mechanics will replace parts until something is fixed. That's an expensive way to diagnose and it's at the cost of the customer. Good technicians will test, test, test until they know what has failed.

Good luck and please let us know what you find. I know I'm curious to know.

Thanks,
TeJay

twinboat 06-03-2021 11:41 AM

Was this a problem before you replaced the brake pads and rotors ?

eastkytriker 06-03-2021 03:02 PM

sticking brakes
 
I bought the MH in Florida and drove it a thousand miles home with no brake problems except shaking from warped rotors, got them replaced with new and new pads and drove it about 20 miles and everything good. So we were planning a trip so l drove it about 4 miles to get propane tank filled and all 4 wheels were smoking. Going to replace the MC and flush the system. You can take a screwdriver and pry the pistons all the way in to the calipers with little effort. Kinda wondering about Anti lock box but don't have any knowledge there other than they are very expensive. Is the proportional valve only installed for motorhome or is it a common part in a E450

TeJay 06-03-2021 08:25 PM

Prying the caliper pistons into the housing is not a difinitive way to determine if the caliper square cut seals are working. Your prying effort are a lot more than is needed for the seal to distort then return to it's original position automatically. I'm sure you can see that.

I'll again say this. You don't know if the stock calipers have been rebuilt. Even if they haven't all the extra heat they have experienced recently may ruin those seals anyway.

I'd start with a complete flush before you replace the MC. There may be a stoppage somewhere that is affecting all 4 wheels. Flushing may solve the issue or not. The symptoms for a defective MC is not building brake fluid pressure. You can stop the vehicle so the MC may be OK. It's just not releasing the pressure.

Follow the symptoms don't just start replacing parts. The MC will usually split the wheel pressures. Over the years the manufacturers did things like apply pressure to both fronts first then to the rears. Sometimes they did a split by applying fluid to the LF and the RR with one port and the opposite with another port. If a leak occurred in a line you'd only loose one set of wheels. The same should also be true if you have a blockage. That was the primary reason why we went to a dual mastercylinder. With the old single clyinder if you had a leak you lost pressure in all wheels.

I'm not exactly sure how the proportional valve is working on the more modern vehicles. I retired 16 years ago and I'm sure things have changed. In addition all vehicles have anti-locking brakes.

spyderRV 06-04-2021 12:46 AM

I had replaced the rubber lines, seals and pads and about a year later I had a front caliper get sticky and overheat. I ordered new seals for the front calipers and cleaned out the caliper bores with a stone reamer. There was a small amount of rust and some friction on the piston. Appears to have solved my issue.


https://live.staticflickr.com/65535/...4b187c3b_o.jpg


https://live.staticflickr.com/65535/...fbb9a72e_o.jpg

andy29847 06-04-2021 06:30 AM

I've had some luck cleaning out the calipers (motorcycle) using aluminum foil.

The one experience I had with sticking brakes and the master cylinder was my pickup at work. The rear most seal on the plunger of the master cylinder was leaking, and fluid was getting into the space between the master cylinder and the brake booster.

Bleeding brakes is different that how I learned when I was a teenager. I have a pressure bleeder (fits at the master cylinder) I use on my motorhome, but the fluid comes out slow. The sudden burst of pressure you get when using the brake pedal and your foot is much better for flushing out contamination.


I used to do the pump 3 times and release pressure at the caliper method. The best method is to have your partner in the cab press on the brake pedal, then you release the pressure at the caliper, partner holds the pedal at the floor, you close the bleeder at the caliper, partner releases the pedal.


Good luck!

TeJay 06-04-2021 06:56 AM

Andy,

Pleased and glad to tell you the best method now is to get speed bleeders which replace your stock bleeder screws with a bleeder that has a check valve. Here's how to do it.

First remove as much brake fluid from the MC as you can and fill it with fresh fluid. Why not? Why pump all that fluid through the system? Remove what you can and pump fresh fluid into the system. I used a turkey baster with a small plastic hose on it so it will get as low into the MC as possible. We removed most of what we could see. Then filled it with new fluid.

Then go to the RR wheel and open the BS (Bleeder Screw) 1/4 turn. Start the engine and pump about 20 times while collecting the fluid into a clear bottle. Pump it untill the fluid coming through a clear plastic tubing is clear/clean then switch to the next closest wheel LR.

If all is working on your RV when the fluid drops to its low level point a light will come on at the dash. When you see that it's time to fill the MC. It takes about 2-3 quarts so have that much on hand.

IMHO this method beats the heck out of all the other methods. I've tried them all believe me. Yes you can use a pressure bleeder and sundry other methods. This method can be done in the 2-4 years again when you need to do another flush. All you'll need is some fluid and a bottle to collect the waste. And you can do it all by yourself and as you mentioned the pressure from the pedal is sufficient to do a better flush.

I just helped a friend do his 2 days ago. We changed each bleeder screw with the new ones (Check valves) as we did each wheel. They will stay in the caliper until you need to do it again in 2-4 years. When it's time to flush again it takes about 45 minutes for a complete flush and it only takes one person doing the pumping and no need to open and close each bleeder as you do the pumping.

Summit Racing has a good selection of valves. The ones for the F-53 are SB3824 part number. The SB stands for (Speed Bleeder). The 38 stands for using a 3/8" wrench on the BS and the 24 means 24 threads per inch.

eastkytriker 06-09-2021 05:45 AM

Thanks for all the info, I have it in the shop now l will update when l have some news but shops are really busy hope summer is not over when l get it back lol.


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