Stupid brakes

[427v8]

OK, I'm getting fustrated, need some advice.

This is a 22' class C on a Chevy G30 1 Ton chassis. It has drum rear brakes, disk fronts.

The brake pedal is very hard, well sometimes.

It seems like if I'm going very slow the brakes are fine, just like a car.

but if I'm doing 30 or more I have to really stand on them. It stops and everything but it just seems to take too much pedal effort.

It has the Hydroboost which I just replaced, it does seem better, but not great.
The front brakes have lots of pad, the rears I haven't got apart yet ( floating axels )

First Question;
This isn't normal is it? What do the brakes feel like on your rig?

What should I check next?
I'm thinking rear shoes?


Keith

 

[Gary RV_Wizard]

Well, you are stopping a lot of weight and it does take a long time to stop it.  And class C's on a one ton chassis or loaded to (or more likle beond) their max weight capacity, so you are really taxing the brakes. Compared to a passenger, it seems to take forever to stop and you have to anticipate traffic ahead of you much more.

However, you may have glazed or oily shoes, both of which reduce braking considerably, even though there is a lot of shoe left.  With drum brakes you can sand down the shoe surface to eliminate he glazing, but since you have to take the wheel off to do it anyway, you may as well just replace the shoes. It's pretty cheap insurance.

 

[Shayne]

Is it possible the vacuum line is not functioning properly.  We replaced our hydrobooster on an older RV we had and it didn't improve. come to find out the vacuum was down .  Late fund a servere leak andalso the carb was carboned up near the vaccumm chamber. Won't cost much the check it.

 

[427v8]

Yea I suppose I'll have to figure out how to pull the drums, big ol things

Shayne,
I don't understand, you say you have a Hydroboost but it sounds like you have a vacuum booster... The Hydorbooster is driven from the power steering pump, not engine vacuum, still I suppose the pump could be loosing pressure, Hmmmm

 

[Karl]

Gary may very well be right about the pads, but you can't always tell just by looking at them; you actually have to sabd them down.

The brake pedal is very hard, well sometimes.

Before that, however, I would suggest a complete bleed and new fluid. You may have picked up some moisture or air along the way. Make sure to start at the farthest brake from the master and work your way back to the closest.

Getting the drums off shouldn't be much trouble if you first back off the adjusters quite a bit. Also helps to tap the drum around the outside with a hammer to break the rust buildup. Sometimes you will find a small clip on one of the studs holding the drum on. Remove it if it's there, and mark one of the studs and the hole in the drum before removing it so you get it back on correctly.

 

[427v8]

Well the drums are those big truck drums not like car drums at all. You have to pull the axle out to get the drums off! Looks to be quite an interesting job. I actually bought an impact wrench to help do it  ;D

The brake fluid looked like mud it was so dirty, I sucked out the resivour and replaced with clean fluid but still need to bleed them. I can't imagine what the stuff in the lines looks like.
I flushed the power steering fluid and I swear it came out in lumps!

I think I'm convinced, I need to pull the drums <yea>

 

[Karl]

Sorry; I thought they would be like car brake drums.

When you bleed the brakes, check the first couple of pumps of fluid at each wheel. If it's muddy down there at the cylinder/caliper, chances are very good you have leaking seals, and they'll need rebuilding. I know that's not what you wanted to hear, but you might as well bite the bullet, rather than having to go back a second time.

 

[427v8]

Well I got the drums off. It looks like the seal(s) are bad as there is oil on the inside of the drum.

So tomorrow I'll be buying new seals, new shoes and about 10 gallons of brake cleaner ;D

 

[Shayne]

Best get lots of Fluid too, and flush out all the mucky contaminated fluid in the process.  If that stuff is that dirty, you are wating $ and energy by not flushing.  IMHO do it right.  Good luck

 

[427v8]

Oh don't worry, I'll be power bleeding a couple of quarts of Dot 5  through the system!

 

[Gary RV_Wizard]

I didn't think the one ton chassis required pulling the axles, but have never actuallyworked on one of those.

Don't use Dot 5 fluid - stay with a good quality Dot 3, per GM specs. Dot 5 is a special application.

 

[John From Detroit]

Well I got the drums off. It looks like the seal(s) are bad as there is oil on the inside of the drum.

So tomorrow I'll be buying new seals, new shoes and about 10 gallons of brake cleaner ;D

If the seals are bad, best have the cylinders looked at by a professional, may need to be honed or replaced

 

[Chet18013]

If the rear brake shoes have oil on them, just replace them. You'll never get them clean and they will just glaze over when you apply the breakes after cleaning.

Chet18013

 

[427v8]

Update...


I got both rear brakes done, it feels much better not racecar brakes but no longer scary...

Both inner seals were leaking getting oil on the pads. I cleaned and resurfaced the drums and replaced the pads. I still need to bleed them but I think they are as good as they will get...