Calling All Gear Heads -Need Brake Drum Help

[Travelover]

I'm adding brakes to a trailer made by UHaul, so it is a little of an odd duck. They used 93 Camaro sealed front hubs for wheel bearings on a 4.75" bolt circle.

My problem is that I need to find some brake drums that will slide over the hubs (like the rear drums on a RWD truck) that are 10" diameter and fit the 4.75" bolt circle. UHaul made another trailer with these hubs and brakes, so I know they exist, but are now obsolete from UHaul. I'm sure they just adapted some drums from another application, but I need help figuring out what that might be.

Why not just use Camaro drums? Camaro drums are 9.5" and electric brakes only come in 10" and 12" sizes.

Any suggestions?

 

[deerefan]

I'm adding brakes to a trailer made by UHaul, so it is a little of an odd duck. They used 93 Camaro sealed front hubs for wheel bearings on a 4.75" bolt circle.

My problem is that I need to find some brake drums that will slide over the hubs (like the rear drums on a RWD truck) that are 10" diameter and fit the 4.75" bolt circle. UHaul made another trailer with these hubs and brakes, so I know they exist, but are now obsolete from UHaul. I'm sure they just adapted some drums from another application, but I need help figuring out what that might be.

Why not just use Camaro drums? Camaro drums are 9.5" and electric brakes only come in 10" and 12" sizes.

Any suggestions?

Try rear drums from same model year S-10. I believe they will work.

 

[Car Doc]

My brake spec book says S-10 drums are 9.5 but some C-10's from 88-91 had 10" rear drums. Don't know if they are 4 3/4 BC though but a machinist could redrill whatever bolt circle you need easy. hth

 

[chucko]

there are add on disk and maybe even drum brakes for boat trailers.. Check somewhere like west marine

 

[Travelover]

Does this jog any memories?

Here are all the vehicles that use a 4.75" bolt circle:

1987-82 BUICK - Regal
1985-79 Riviera
1985-77 LeSabre (Ex H.D. Pkg.)
1983-61 Century, Gran Sport, Regal, Special, Sportwagon
1979-73 Apollo, Skylark
1985-79 CADILLAC - Eldorado
1985-80 & 76-75 Seville
1996-87 POST OFFICE VEHICLE - GM
1999-83 CHEVROLET - "T" Series (4WD), Blazer, Pick Up
1998-82 "S" Series, Durango, Sport, Tahoe, Pick Up (2WD)
1995-66 Camaro, Berlinetta,
1990-77 Caprice, Impala, Belair, Biscayne, Kingswood (WO/H.D. Pkg.)
1989-70 Monte Carlo
1987-69 El Camino
1985-65 Malibu, Chevelle, Laguna
1982-68 Corvette
1981-67 Camaro Z-28
1981-66 Chevy II, Nova
1999-83 GMC TRUCK - "T" Series (4WD)
1998-82 "S" Series, S - 15, Seierra Classic, High Sierra, Gypsy, Jimmy, Pick Up (2WD)
1979-71 Sprint
1998-96 ISUZU TRUCK - Hombre
1994-91 OLDSMOBILE - Bravada
1987-69 Cutlass, F85, 442
1985-79 Toronado, Toronado Trofeo (FWD)
1985-77 Delta 88, 98 Regency
1994-71 PONTIAC - Firebird
1986-77 Catalina, Executive, Safari Wagon (WO/H.D. Pkg.)
1986-71 Bonneville, Grand Prix, GTO, Lemans, Tempest
1980-69 Trans - Am
1979-71 Ventura, Phoenix (RWD)

 

[Travelover]

there are add on disk and maybe even drum brakes for boat trailers.. Check somewhere like west marine

Thanks, I've looked there. I'm adding electric brakes, so discs won't work.

 

[Car Doc]

Does this jog any memories?

Here are all the vehicles that use a 4.75" bolt circle:

How many have the 10" drum or am I missing what you are looking for?

I didn't see any cars listed as having 10" I looked thru all of GM from 1970-2000 but you might check Raybestos or one of those sites for more specs but like I said I couldn't help ya.

 

[Travelover]

How many have the 10" drum or am I missing what you are looking for?

I didn't see any cars listed as having 10" I looked thru all of GM from 1970-2000 but you might check Raybestos or one of those sites for more specs but like I said I couldn't help ya.

Car Doc, thanks for looking. As far as I can tell, none of these listed have a 10" drum - lots of 9.5" and 11" (I'm looking at the Rock Auto site).

I'm sure UHaul didn't make up their own part, though, so there has to be an off the shelf part, if I can find it.

 

[Car Doc]

I'm sure UHaul didn't make up their own part, though, so there has to be an off the shelf part, if I can find it.

Welcome, you would be surprised how many short runs of special order parts these big company's can get done at a big parts supplier it could well be any 10" drum and 4 3/4 BC with the proper hub center cut in.

I could easily do a couple drums on my brake lathe and draw a new CL around the face of the drum and simply correctly locate and drill the new spacing on a Chevy PU drum if I needed too so anyone can do it if none can be found its not a huge deal really :thumbsup::thumbsup:

(I wouldnt want to go into production but a one of two of would be no biggy)

 

[kenmac]

have you tried here https://www.etrailer.com/. I,ve used them several times for trailer stuff

 

[Travelover]

have you tried here https://www.etrailer.com/. I,ve used them several times for trailer stuff

Thanks, yea, I checked there. Lots of bearing in hub drums, but I need a free floating drum.

 

[Travelover]

........ Don't know if they are 4 3/4 BC though but a machinist could redrill whatever bolt circle you need easy. hth

I may end up doing this. A 1980 Granada drum has the right hub center hole diameter and a 10" brake face, but a 4.5" bolt circle. I could elongate the holes and the hub would still center it.

 

[Gary51]

Would it be any easier or cheaper to just swap out the whole axle for a more standard size?

 

[Travelover]

Would it be any easier or cheaper to just swap out the whole axle for a more standard size?

Thanks for the suggestion.

My thinking: A whole new torsional axle with brakes would be about $400+ shipping, and I'd have to modify if to fit. I bought brake assemblies for $60 (Eastern Marine). Brake drums are about $60, so this seems like the easier and cheaper path.

 

[Car Doc]

I may end up doing this. A 1980 Granada drum has the right hub center hole diameter and a 10" brake face, but a 4.5" bolt circle. I could elongate the holes and the hub would still center it.

Good find! Here is a suggestion on how to do it right with a bit more work-

(w/o elongating any holes which would work fine and be fairly easy but imho for me anyway wouldn't be very sanitary)

Knock out the studs on the hub and set the hub into the drum backwards and scribe the bolt holes onto the drum face between existing holes and just center punch and drill them. :thumbsup:

 

[Travelover]

Good find! Here is a suggestion on how to do it right with a bit more work-

(w/o elongating any holes which would work fine and be fairly easy but imho for me anyway wouldn't be very sanitary)

Knock out the studs on the hub and set the hub into the drum backwards and scribe the bolt holes onto the drum face between existing holes and just center punch and drill them. :thumbsup:

Great suggestion. I would hate the look of elongated holes.

 

[Car Doc]

I would hate the look of elongated holes.

That's kinda what I figured. :thumbsup:

Just turn the lug nuts around to the flat side and pull the studs back in use a little motor oil to slick them up make them go back in easier. I sometimes have to use washers under the nuts if the threads dont go down far enough on stud installs. hth

 

[Travelover]

I ordered a set of electric brakes. Once I have them, I can figure out which drum will fit inside the space I have.

I'll post back as I progress.

 

[Hooked_on_HP]

I think you are over looking a majior problem. On drums for electric brakes the face of the drum where the magnets rub is machined flat. I have never seen a car or truck drum like that.
Bill

 

[Hooked_on_HP]

You are going to have to go to an integrated drum&hub assembly for the electric brakes to work. The next problem is that all of the drum hub assemblies are 5 on 4 1/2. Now your rims won't fit The other problem I see is the width of the brake shoes.The shoes have to match the drums. You might be better off adding surge brakes. Then you could use automotive brake assemblies.
Bill