Old IH axle stuff

[Jarlaxle]

The truck: 1979 IH S1700 wrecker, DT466/5-speed, hydraulic drum brakes, no Jake. Wheels are old 10-lug 20" splits (front uses 5 lugs like a Chevy 3500HD) with 9.00R20 tube tires. The basic problem is the brakes: with something heavy on the hook, it, well, doesn't have any. Chuck has a line on a wrecked 1987 IH S1700 school bus (gas 345/auto & a Carpenter body, if it matters) with 4-wheel disc brakes & 10-lug Budds. My basic question is: will the school bus axles (or at least the disc brakes) swap onto the 79 without more 4-letter words than usual? Would a 2-speed axle require a different housing, or just a new centersection?

Also, how hard is adding a Jake (or an exhaust brake) to a mechanical 466?

 

[towcat]

I'd be swaping pronto. A new set of U-bolts and I am dangerous My chev 1ton w/holmes 440 was a good truck but paled in comparison with the stopping power to my F450. 2nd issue are the "widowmaker" rims on the wrecker. I started in heavy diesel repair years ago as the "tire boy". Hated those rims, lived to tell about it. check ratios on both to make sure you won't be having a problem with getting out of your own way.

 

[Jarlaxle]

The rims are no biggie--the HD rollback is a 1972 F-800 (361FT gasser) that has Daytons with 10.00R20 tube tires (and Rockwell StopMaster wedge brakes that will put you through the windshield). The tire guy is used to our weird trucks. Having said that, the truck may get the 10R22.5's from the bus.

And I was wrong--the IH doesn't have 9.00R20's...it has bias-ply 9.00-20's.

I'm hoping the wrecker centersection will fit the bus axle, since I figure the bus, being a gasser & a school bus, may have gears in the 5.89-6.17 range (the wrecker has, IIRC, 4.10's). Even with the wrecker's highway gears, power is no problem (215HP)

 

[towcat]

If it was up to me, and I'm about a lazy of a builder as you can get, measure up the spring pads and if they're the same, do a complete swapover. Unless if the housings don't measure up, why deal with all that work and gear oil if all you have to do is roll one axle out and another in. BTW....that's a big jump in ratio numbers. That DT is going to be running outside of its powerband and you will be screaming as you are barely doing 55.

 

[Jarlaxle]

That's why...

I'm hoping the wrecker centersection will fit the bus axle

I'd much rather just swap the brakes, at least in back, because otherwise it will be a bunch more money to swap gears (and yep, the bus has 5.89's). Also, would the steering linkages be the same from 1979-1985?

Also, what about the master cylinder? I know the drum master won't work, and the bus has a vacuum booster. Would it be as easy as getting a master for, say, a 1985 S1700 with a diesel?