NOMADICISTA

I need to adjust the brakes on my rig. I hear it is easy but not knowing exactly what to do I would love some advice! They are air brakes..I am told the pads are ok...just need to adjust them.
Thanks ~ Bob

Bob wrote:I need to adjust the brakes on my rig. I hear it is easy but not knowing exactly what to do I would love some advice! They are air brakes..I am told the pads are ok...just need to adjust them.
Thanks ~ Bob

Scroll down to the bottom of the page, Sharkey posted some links there that might help.

http://www.mrsharkey.com/forum/vwtp.php ... ght=bendix

Drop Longjohn an email. He seem to be pretty good with that stuff

Before you start to adjust your brakes (assuming they are air brakes) you need to know if the brakes on your rig are 'S'-cam or Wedge-type air brakes.

If you have discs you have pads. If you have drums you have linings.

It all makes a difference.

If you need direct help, drop me a line or give me a call.

Many thanks to you all! Longjohn gave me that "special" help via the phone to complete the job...I appreceate it VERY much! Now that I know how to do it I will keep better tabs on the brakes....no more using dump trucks to stop!

Bob
Glad that i could help. Sorry i was doing twenty things when you called hope this helps for future adjustment. for many years i hauled wood chips and might hook to 10-15 different trailers in a weeks time, small ball peen and 9/16 right besides drivers seat.When hauling Perdue chickens always used "Uncle Franks" brakes first ........Glad to be of help.....lj

Longjohn,
You reminded me of something an old trucker told me some years ago. Speaking of the hand-valve on a truck, he said, "that's how you stop when you're pulling a rented trailer".

That's right,That's right ,Truck Driver

Ok, I know I was wrong to buy a bus with hydraulic brakes but I did anyway. Does anyone have any ideas why my front wheels are taking turns locking up when I barely step on the brakes? I did have leaking wheel cylinders. I fixed them and bled the brakes thoroughly. I have heard that contaminated brakes will grab but I don't get why it's one wheel at a time. I think I may still have hydraulic gremlins somewhere.

Disc or drum?

Gummy brake shoes on drum brakes can give loads of trouble if they have been saturated by oil or brake fluid. The only proper repair for such shoes is to replace them. Have the drums hot tanked and then turned as well.

How is the remainder of the brake hardware? Rusted/sticky parts? Old flabby return springs? If disc, are the caliper pins/retainers smooth and free in operation?

Please don't tell us that you "fixed" your brakes by "rebuilding" the wheel cylinders. Replacing brake cylinders/caliper assemblies is the only recommended repair these days. Too many failed "rebuilds" with old/pitted cylinders.

Make sure everything is clean and dry, no gummy pads/shoes, no warped drums/rotors, wheel bearings in good adjustment, etc.

I did rebuild 5 them(wheel cylinders). Mostly because I needed 6 of them. I have had the wheels back apart and they aren't leaking yet but I am sure some of them will. Back to back surgeries have made me temporarily poor. What's really confusing me is first , the driver wheel was locking. I took it apart and checked it out. I lubed the backing plate contact points and checked adjustments. All was ok then the other wheel did it. I checked that wheel out and now the driver side is at it again. I guess I should have learned air brakes. Then I could have spent years looking for an inexpensive old shortie with air brakes. I've never had so many problems with hydraulic brakes. I've owned alot of vehicles. I'll figure it out but right now I feel like I am chasing my tail.

On the bright side, when I do head out on the road, I will have a thorough understanding of how my brakes work, and lots of new parts.

teamgreen wrote:On the bright side, when I do head out on the road, I will have a thorough understanding of how my brakes work, and lots of new parts.

Thats exactly how I feel! I learn more and more from the folks here and by trial and error...or perhaps "errors?" I knew every nut on my old Class C's gassers...and I am learning about big rigs all the time.

If your bus sat for awhile with leaking wheel cylinders, you might have thick areas of rust in the drum. Break fluid is hydroscopic, so a drum can rust pretty fast if it has brake fluid on it.

When you apply the brakes the first drum to hit the brake shoes (left or right) at the rusty spot will lock up.
The drum in the rusty area is built up with rust, making it a smaller diameter. If the drum is out of round or warped as Sharkey said, it can lock up.

If it was driven with oil or brake fluid on the shoes, the drum can get hard spots. These spots are actually heat treated into the drum. If that happens it is best to replace the drums, not try to repair them on a lathe.

One more thing that can cause a low brake pressure lockup, is if inner lining of the brake hose is deteriorating. Little cloth hairs can move with the flow of brake fluid and plug the passage of fluid (acting much like a check valve) all the pressure will be applied to the opposite side causing it to lock.


Chuck

Thanks for the ideas. Ive had the "check valve" problem on a motorcycle before. It would build pressure with friction heat and lock while going down the trail. I'm hunting for some more parts I guess. The linings are definitely contaminated. I've never had this problem with contaminated shoes before but they worked much better after I cleaned the shoes and drums with emory cloth(very temporary repair). Because this is an odd size bus (B500), parts hunting is sort of tricky.