77 disc brake problems

[tschat]

I just bought a rather run down 77 excella 500. I don't think the brakes have been used since it left the lot. It has the older vacuum/disc configuration. The rust is quite thick on the disc's/etc. Is it worth trying to convert this system over to an electric master cylinder and keep the disc, or should I just remove everything and go to an electric drum configuration?

-thomas

[Excella CM]

Those vacuum over hydralic disc brakes were great and some folks really like them still. If the rust is not too deep on the rotors you'll be OK just running them until they polish, or maybe having them machined. They are part of the hub, and not readily replaceable so don' t go too thin if you machine them. The vacuum over hydralic actuator is getting tough to service and if it doesn't function, many folks replace it with a modern electric over hydralic and keep the calipers and rotors. Vacuum brakes need a source of vacuum (mainfold or pump, if it's a diesel) at the rear bumper as well as the electrics to activate the master cylinder. Electric over hydralic need only the electrical. We're still using the original system. Parts are available at reasonabe prices from jobbers from the original manufacturer Ausco (see other posts on similar themed threads)

Good luck.

If you scrap it out, let me know, I'll buy your old system or parts thereof

Regards,

[uwe]

I would keep the discs, if at all possible. I second the previous post on your choices.
Take alook at this disc brake comparison attachment from back when these trailers were new.

[dwightdi]

I scrapped mine out on the 77 after repeated failures on the road and inability to find people to fix them when on the road. Final straw was failure of 2 of 4 caliper holders. The welds holding the slider pins developed fatique cracks. Trailer had lots of miles on it and we hoped for lots more on longer trips away from home and parts suppliers. Electrics (with proper controller) worked almost as well and were reliable. Alot has to do with performance is the choice of controller and proper adjustment. Readjust based on road conditions and type of driving.

[amx_man]

I have the hydraulic disc brakes and they rattle like crazy but stop rattling when the brake is applied. Work better than any electric brakes I've had in the past. No grabbing, even pressure but I can't find anyone to work on them. What is the best approach to replacing them with electric?

[Phil Gobie]

I have a 77/31. The brakes had been switched to electric drum from the factory disc/vacuum system. I put on disc with electric hydraulic. I was able to re-use the hydraulic lines which made the installation very easy. I would think you could do yours with just changing the master to a electric pump. Be sure you get a compatible controller for your tow vehicle.

[Excella CM]

Think twice before trashing the whole system. The calipers are still current and all the parts are available for them. You can replace the HydraVac unit with and "ElectrVac" type so that you get it serviced by dealers.

[JimGolden]

Disks do work better than drums, no argument there.

I would forget the hydrovac unit altogether and get a modern electric over hydraulic actuator, like the one from Actibrake, Dexter, or (my favorite) Towbrake.

The brakes are made by Ausco. Inland RV has most parts for them. The hubs are not replacable with new ones. Inland does have some cleaned up old ones, but there are no new ones. If you wanted to, you could try machining the rust off the ones you have. If you can save them, then you could use them. If they're not salvagable, then I'd go to...

Plan B. Your axles are most likely shot anyway. Order a new set of axles from Dexter and have them equipped with new Dexter disk brakes to start with. Then either have them send you a Dexter EoverH unit, or buy one of the other brands. I believe Inland Andy sells new Henschen axles with Kodiak disk brakes on them and can send you an Actibrake controller. You can get one stop shopping from either him or Dexter.

Another option would be Kodiak disk brakes. You could put those onto bare axles, whether they be from Henschen or Dexter. Then get an E over H and you're set.

You could even put your old ausco brakes onto new axles.

If I were in your shoes (I am actually), I'd get new axles with new disk brakes and a new E over H unit and run all new brake lines and call it good.

You'll have probably $2K in doing this.

If that's too much, then I'd get the heavier Dexter axles derated to the weight you need and go with the 12" electric drum brakes. You could always change the brakes later on and the electric drums work well. It'd get you camping now. But if you have the green, look at a totally new set of axles with new brakes and E over H.

Best of luck!

[Phil Gobie]

Jim nailed it on the head. I did use my old brake lines (flushed out). This saved me from running all new that would have involved removing the belly or running externally.

[Inland RV Center, In]

Originally Posted by tschat

I just bought a rather run down 77 excella 500. I don't think the brakes have been used since it left the lot. It has the older vacuum/disc configuration. The rust is quite thick on the disc's/etc. Is it worth trying to convert this system over to an electric master cylinder and keep the disc, or should I just remove everything and go to an electric drum configuration?

-thomas

Going to electric brakes would be a huge step "backwards" especially in safety.

We have many parts for the original Airstream disc brake system, pads, bushings, clevis pins, pistons, boots and "O" rings.

The "Sync" valve may need an overhaul, if the trailer was parked for years. Many miles on the system might also need a caliper overhaul. We do that too.

Andy

[davidz71]

I agree with Andy on the disc brakes. After I plumbed my truck with airbrake hose and 1/2" industrial couplings for the vacuum requirement, installed the Hayes-Lemmerz Energize III controller recommended and purchased from Inland RV, my brake system worked perfectly with no problems for 4 years before selling it to an individual in Germany.