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View Full Version : TT- Brakes - Self adjusting???



TeJay
02-07-2011, 06:58 PM
Hi,
I have searched the forums gathering all kind of mechanical information in preparation for taking delivery of our new 24-RBS. With 40 plus years of teaching & learning automotive mechanics it's second nature to learn & be prepared for this new adventure.

Since my first VW in 1960 I don't think I've seen a drum brake system that was not self-adjusting. If they needed adjusting they did so after applying the brakes while backing up. The shoes shifted which adjusted the star wheel up one notch. They would continue to adjust until the shoes wore down completely & on into the drum. It was usually the horrible metal to metal scraping sound which alerted people to the problem.

I don't have much experience with trailer brakes but I did read a forum that said to adjust the star wheel to get the shoes close to the drum then back it off about 5 clicks.

I guess I'm confused. Are our brakes self-adjusting or do we need to keep the trailer brakes adjusted?

One more item. I will only use full synthetic bearing grease for any or all bearings. I prefer Mobil-One. I have used their engine & gear oil for 35 years. I can furnish more info regarding that subject if anyone is interested. E-mail me.

I'd appreciate any information regarding the brakes.

Thanks,
TeJay

branson4020
02-07-2011, 07:10 PM
Trailer brakes are NOT self adjusting.

wyleyrabbit
02-07-2011, 09:25 PM
Would be great if someone could put together a nice step-by-step on how to do this. I'm mechanically inclined, but not trained in how to adjust trailer brakes. Would love to learn.

jmgratz
02-07-2011, 10:53 PM
On the back of the backing plate there is a rectangular slot which should have a rubber cover on it. Pop off the rubber cover adn insert a brake adjusting tool (a regular flat screwdriver will work in a pinch). You will want the wheel to move from the ground up (I think) to tighten the brakes. So you would insert the tool at a downward angle and then pull the handle of the tool down causing the wheel to rotate. You should have the wheel off the ground so you can move the wheel. Keep adjusting and spinning the tire until the tires drags. Then back off the adjustment about 1/4 turn. Do that for each wheel. Takes a few minutes but it is not hard. After you finish adjusting test the brakes in a safe location.

wyleyrabbit
02-08-2011, 08:51 AM
Jim,

Is the backing plate on the inside of the wheel?

Cheers

boatto5er
02-08-2011, 09:28 AM
Not Jim, but yes it is. It is literally the cover for the back side of the brake assembly. If you do this yourself, it is critical that you have the trailer supported by jackstands because you will be under it.

caissiel
02-08-2011, 09:37 AM
While adjusting the brakes would be a good time to grease the hubs. If you use the zurk fittings you will need to rotate the hubs so the grease will not push the seals off the hub and create a mess inside the hubs.

Mine was not greased properly when I received it and I almost ruined my brakes and had to to do maintenance to the brakes on the road to Florida last year.

TeJay
02-09-2011, 09:21 AM
Ok,
Thanks for the reply that TT brakes are not self adjusting. Now I'm even more confused. Since the technology to make them self-adjust has been around forever why are they not self-adjusting?? There must be a good reason but I'm not sure why. It may have something to do with the fact that since they are so far away, isolated from the TV & our ears we can't hear them scraping if they advance into the drums. If not corrected this will damage the drums to the point of needing replaced. This would be costly. Or it may have something to do with the magnetic actuating aspect of the trailer brake system. I have only worked on one trailer brake system in all my years of mechanical repair so I do have limited experience. I have looked some on the net but still have not received a definitive answer. Can somebody enlighten me???
Thanks,
TeJay & Liz

jmgratz
02-09-2011, 09:26 AM
Have you ever tried to back up a 40' 5er to adjust the brakes? No safe at all. That is the reason. It is a safety issue. If you want to have self-adjusting brakes then why not convert your brakes from drum brakes to disc brakes. IMO disc brakes work better and stop better. I know they cost more but to me it is worth it.

mountainlovers76
02-10-2011, 11:15 AM
Have you ever tried to back up a 40' 5er to adjust the brakes? No safe at all. That is the reason. It is a safety issue.

They make self-adjusting brakes that adjust through the forward motion. I just purchased a set and will install them soon to see how they work.

TeJay
02-10-2011, 09:22 PM
When I was teaching I learned lots of stuff from my students every day. Since I retired 5 years ago I don't always get those enlightening moments, but today I did. Thanks for the information. I'll file it and move to the next item that I don't completely understand.

Thanks,
TeJay

jmgratz
02-10-2011, 09:48 PM
They make self-adjusting brakes that adjust through the forward motion. I just purchased a set and will install them soon to see how they work.

Thanks for that info. Did not know that. It would be interesting to see how they work to keep from over-tightening. Guess that is why I was not an engineer.

TeJay
02-23-2011, 08:18 PM
Jim,
Here's how self-adjusters work.

The brake shoes are held tight to the anchor pin at the top of the backing plate with stiff retracting springs. Today's brakes are also called, "Self energizing." The next time you do brake work and have the drum removed grab both shoes at the bottom and move them. The bottom of the shoes will shift about 1-2 inches front to back on the anchor pin. When you apply the brakes the shoes make contact with the rotating drum and will pivot on the anchor pin until the rear shoe makes contact with the drum. Because of the rotation of the drum the rear or secondary shoe is then pulled into or wedged against the spinning drum. That is the self-energizing or wedging action. It creates more friction and therefore better stopping power. Have you ever noticed that most of the time the rear shoe is always worn more than the front shoe?? In many instances the rear shoe is also bigger or longer than the front. That shifting or wedging motion happens going forward or backward. How do they self-adjust??? Remember the shifting action. As the shoes wear thinner they will shift more and more. As they shift they will pull on a self-adjuster cable attached to the anchor pin at one end and a lever next to the star wheel at the other end. Once it has shifted sufficiently the lever will contact the star wheel tooth. When the pedal is released a spring will pull the lever down moving the shoe out one notch. That happens every time there is sufficient movement to allow adjustment to take place. Most cars and trucks adjust after backing up but it could be set up either way. As far as backing up a trailer just to adjust the brakes well we wouldn't do that. However if we did have self-adjusters when we do have to back our trailer and apply brakes to stop they would adjust if needed. Or as mentioned they do have self-adjuster kits available that adjust going forward.

I hope this makes sense
TeJay