63.5mm caliper identification - need return spring

[Christo]

Can anyone identify this caliper? I have 6 wheel disc brakes with Lambke-style forked caliper mounts and this photo matches my rearmost calipers. The slide is from a deck by Albert Branscombe that discusses improving Manny's reaction arm system. I'm searching for a return spring for the parking brake lever on the driver's side and would also like to figure out the caliper part number in case I ever need to replace it.

 

[pvfjr]

I recall from my 4x4 days that Eldorado calipers were often used for rear disc brake swaps on Corporate 14-bolt full floating 1-ton rear ends. They were some of the only large calipers with mechanical parking brake provisions available in the early 2000s (they're more ubiquitous now with modern trucks coming with rear discs from the factory). I'd guess they were from 70s Eldorados IIRC?

 

[pvfjr]

Not All Eldorado E-Brake Calipers Are The Same | Lugnut4x4

Many truck Owners seek out Eldorado brake calipers When upgrading their trucks Drum brakes to Discs. Here's what you Need to know if you're Planning to make the Swap.

lugnut4x4.com

The article mentions the factory parking brake lever being plagued with problems, as well as many of the reproductions that copy it. So there's likely to be some variations on that solution in some of the aftermarket companies that improve on the original design. Could be custom to some degree.

 

[Christo]

I recall from my 4x4 days that Eldorado calipers were often used for rear disc brake swaps on Corporate 14-bolt full floating 1-ton rear ends. They were some of the only large calipers with mechanical parking brake provisions available in the early 2000s (they're more ubiquitous now with modern trucks coming with rear discs from the factory). I'd guess they were from 70s Eldorados IIRC?

Yes, I've been doing some more research. These calipers are the 'large' calipers from the 76-78 Eldorado: Piston Diameter 2 13/32. Opens to 1.3 inches 7 inches center to center for the mounting pins. Banjo Bolt thread size 7/16-20. I haven't found a source for the springs, but Rustic Disc Brakes makes a replacement that changes the lever/spring mechanism. Some GMCMH rear disc brake systems used the smaller caliper from the 79-85 Eldo.

 

[Christo]

Not All Eldorado E-Brake Calipers Are The Same | Lugnut4x4

Many truck Owners seek out Eldorado brake calipers When upgrading their trucks Drum brakes to Discs. Here's what you Need to know if you're Planning to make the Swap.

lugnut4x4.com

The article mentions the factory parking brake lever being plagued with problems, as well as many of the reproductions that copy it. So there's likely to be some variations on that solution in some of the aftermarket companies that improve on the original design. Could be custom to some degree.

PHENOMENAL article. Thank you!!

They have another interesting article about how these parking brake calipers require specific D122 brake pads with 'nubs' that fit into a recess in the piston to keep the piston from turning and affecting the adjustment of the parking brake: https://lugnut4x4.wpenginepowered.com/brake-pads/d52-vs-d122-brake-pads/

 

[pvfjr]

PHENOMENAL article. Thank you!!

You're welcome.

Ah yes, I remember now, it was the 76-78 "large" (2.5" or 63.5mm) calipers that were getting very hard to find, and were quite expensive even used or rebuilt. They were the holy grail of the junkyard. But everyone wanted them for their 40" Super Swampers. I ended up with 3/4-ton front calipers and a line-lock, since it's what I could afford at the time.

The 80s calipers were much easier to get, but on the puny side for large mud tires (or motorhomes, I would think).

 

[pvfjr]

 

[Christo]

Oh, and they sell just the conversion kit that includes a better-made lever/spring/bracket @ $60 for both sides:

Emergency Brake Hardware Kit |14 Bolt Disc Brake Kit | Lugnut4x4

Do You Have A Set Of Calibers That Are Compatible With Your eBrake, But Need New Hardware? This Hardware Kit Is For You.

lugnut4x4.com

You're my hero today, Paul!

 

[Christo]

None of the springs in that kit match up with the one good spring I have, so I think I'll stick with the lugnut4x4 kit.

 

[pvfjr]

Oh, and they sell just the conversion kit that includes a better-made lever/spring/bracket @ $60 for both sides:

Emergency Brake Hardware Kit |14 Bolt Disc Brake Kit | Lugnut4x4

Do You Have A Set Of Calibers That Are Compatible With Your eBrake, But Need New Hardware? This Hardware Kit Is For You.

lugnut4x4.com

You're my hero today, Paul!

Glad to help. I actually ran into a 20 year old forum post of mine on CK5.com!

I think the conversion kit is a good idea. I'm not sure what the current total cost of all the hardware is from that YouTube short, but it's probably close to the conversion kit. You may as well change things over at that point.

 

[billvv]

Bruce's Ford F-150 electric-hydraulic caliper kit (that he took over from Branscomb) is working great for me.