1959 GMC 2 ton bus - 4x4 swap

[arse_sidewards]

I really like this front axle build.

 

[WaterH]

Really cool stuff going on here. I like the bottom truss. I know people say it loses ground clearance, but I has the benefit of being in tension. The only thing I don’t like is the tie rod being low. just because the truss is in front doesn’t mean it’s protected. But if it’s the only way you could work it, it will have to do.

 

[thatbus]

I really like this front axle build.

Thanks!

Really cool stuff going on here. I like the bottom truss. I know people say it loses ground clearance, but I has the benefit of being in tension. The only thing I don’t like is the tie rod being low. just because the truss is in front doesn’t mean it’s protected. But if it’s the only way you could work it, it will have to do.

That's exactly why I went with the bottom truss; I need this axle to carry a lot of weight, more than I need it to have amazing ground clearance. I have 42" tall tires anyways. No threat of buckling with a truss acting in tension.

I hear ya on the tie rod. I couldn't mount it upside down because it'd interfere with the leafs. However, I think I can angle it back a bit so the lowest part it sits just below the pinion.

 

[pennsylvaniaboy]

Any opinions on Mile Marker 459SS lockouts? On a tight budget and the Warn 62672 are too pricey when I take into account shipping + exchange + taxes up north here...

I have these hubs on a DD excursion. I have no complaints, they even come with a tool to help turn the dial. Any normal dana 60 lockout will work. A cheap junkyard option is the mid 90's TTB50 lockouts

 

[thatbus]

I have these hubs on a DD excursion. I have no complaints, they even come with a tool to help turn the dial. Any normal dana 60 lockout will work. A cheap junkyard option is the mid 90's TTB50 lockouts

Thanks. I actually ended up getting the Warns in a trade - brand new ones!

For anyone curious, a 12" cylinder is what you need for a D70... it works perfectly, literally a few millimeters past the original stops, but holy shit does it take up a lot of space:

I'll probably get a different ram in the same size for 2/3rds of the price and better inlet locations, this was just to size it up.

 

[WaterH]

That clamp on ram mount looks really fancy, but I’m not sure I would trust it. Does it have any kind of key into the tie rod?

 

[thatbus]

That clamp on ram mount looks really fancy, but I’m not sure I would trust it. Does it have any kind of key into the tie rod?

Agreed. I've sheared half the screws off lol. I plan on welding the bottom of the clamp together, while keeping the top open. I'll then weld two plates onto either side of the top, and add a couple 3/8 bolts to clamp it together.

It'd be similar in function to this:

I'll probably also tap set screws into the wall of the clamp, to keep it located.

 

[thatbus]

Small update.

Changed up the tierod cylinder mount to be more robust. Gusseted and added two 3/8-16 screws, turned the thing into a clamp basically.

I also managed to move the tierod above the axle. That was more work than I expected, but it allowed me to get 31° steering, yeah not much more than stock, but it's out of the way, and it's a touch more...

Getting the tierod and hydraulic cylinder length and mounting all dialed in was a three day affair of adjustments. This 12" tierod cylinder was able to be made about 1" shorter than the red cylinder, with minimal work. Having enough tierod to clamp to on the driver side, while having the shortest length before the upwards bend, on the passenger side, was tough to balance, as either lead to a loss of steering angle. Glad I finally got it.

Also ran into issues with the yoke having a healthy clearance from the tierod. Since increased from the photo above (3/8") to 3/4". I think that's good enough.

If anyone has tips on how best to connect my hydraulic steering and brake booster, that'd be appreciated... I'm thinking -6 JIC from pump to Hydromax brake booster, -6 JIC from booster to Sweet Mfg steering servo, -6 JIC from steering servo to filter, -10JIC from filter to tank, -10 JIC from tank to pump?

 

[thatbus]

We've got disk brakes now (well, tacked together). Largest to ever go on a Dana 70, far as I'm aware.

If anyone wants the .dwg files to laser cut their own kit, I'd be glad to share them.

 

[arse_sidewards]

Post them up to the CAD library (click on "Resources" in the top bar then look at the left sidebar).

I like that you designed blank plates so anyone can make them fit any caliper by mocking it up and then welding on different tabs.

Does the D70 you have use the same bolt circle for the spindle as a D60?

 

[thatbus]

Post them up to the CAD library (click on "Resources" in the top bar then look at the left sidebar).

I like that you designed blank plates so anyone can make them fit any caliper by mocking it up and then welding on different tabs.

Does the D70 you have use the same bolt circle for the spindle as a D60?

Sweet, I'll do that.

The D70 stuff is very annoyingly, almost to D60 dimensions but not quite. The seal surface OD is also too large and if memory serves, can be taken down around 10 or 15 thou...The 5-bolt circle on the spindle is slightly different than Ford's, but the ID of the ring/shoulder that locates the spindle and fits inside the bore of the knuckle, is slightly smaller than D60 stuff...

Now, if you opened up that bore maybe 1/8" then you could fit a D60 spindle in there. Never tried it, but what I bet you could do is use a Ford 5-bolt spindle, clock it so the 5 Ford holes are halfway between the 5 D70 holes, and drill 5 more holes; end up with 10 holes, 5 of which can be tapped for coarse x fine studs into the knuckle, just as I did.

 

[Grendel]

What rotor and caliper did you use?

 

[thatbus]

What rotor and caliper did you use?

For the calipers, I used 2005-2016 F-550/F-450 ones. (18-B8047B and 18-B4046B). New enough that there's good future parts availability I figure, and they're used on a few International chassis as well.

For the rotors, I used International 4400 ones. (680943R). They're also used on the majority of medium duty class 5 and up chassis; International CV/Chevy 4500, Ford F650, several motorhomes.

 

[06h3]

Badass front axle. I’m a huge fan of the 70F

 

[Grendel]

For the calipers, I used 2005-2016 F-550/F-450 ones. (18-B8047B and 18-B4046B). New enough that there's good future parts availability I figure, and they're used on a few International chassis as well.

For the rotors, I used International 4400 ones. (680943R). They're also used on the majority of medium duty class 5 and up chassis; International CV/Chevy 4500, Ford F650, several motorhomes.

Aye, I use those calipers on a lot of rigs. Shipped some to shortbus4x4 to go on an Axletech 4K with brackets.

Thoughts over bent brackets instead of welded 3X?

 

[WaterH]

Thoughts over bent brackets instead of welded 3X?

Pics of bent brackets?

 

[thatbus]

Aye, I use those calipers on a lot of rigs. Shipped some to shortbus4x4 to go on an Axletech 4K with brackets.

Thoughts over bent brackets instead of welded 3X?

With bent brackets, I think it'd be easier to ensure parallel planes between the spindle mount and the caliper mount... if you've got a brake capable of 3/8". I don't. But I will accept a donation for testing purposes.

I don't think there would be any difference in strength with the amount of weldement I have (this is why I made the bracket, spacer, and caliper mount tabs in steps - I can get some nice big fillets between each.

Heat control is, by far, the biggest issue with these welded brackets. Been busy doing brake jobs and mobile welding on other's buses until today - I'm only getting around to the final welds now - but even for when I tacked these together, it took a ton of clamping and a bit of hammering to keep everything nice and flat. It seems to be going okay, but only with slow welding, identical beads on opposite sides, and only with the bracket bolted to a spindle and a 3/4" bar clamped to the caliper mounts.

What's that Axletech going under? Sure as shit hope its a bus!

 

[thatbus]

Pics of bent brackets?

I would assume he means this sort of thing:

These are from TMR, for the Ford D60.

Ford Dana 60 Front Disc Brake Brackets

CNC laser cut & formed from 3/8" high steel Utilizes '73 - '87 3/4 ton 4x4 front calipers (RC4072 & RC4071) and rotors (5014R) Sold as a pair (2 brackets) Fits 78-91 Ford King Pin Dana 60, single wheel

ca.tmrcustoms.com

Bet you could actually make these work if the center bore is around 4.880" - no idea what it is on a Ford D60 spindle - and you don't mind redrilling the 5 boltholes.

 

[WaterH]

I would assume he means this sort of thing:

These are from TMR, for the Ford D60.

Ford Dana 60 Front Disc Brake Brackets

CNC laser cut & formed from 3/8" high steel Utilizes '73 - '87 3/4 ton 4x4 front calipers (RC4072 & RC4071) and rotors (5014R) Sold as a pair (2 brackets) Fits 78-91 Ford King Pin Dana 60, single wheel

ca.tmrcustoms.com

Bet you could actually make these work if the center bore is around 4.880" - no idea what it is on a Ford D60 spindle - and you don't mind redrilling the 5 boltholes.

I figured it was something like that. Looks clean and a little lighter. Might be able to make something with a bearing press and a torch, but I don’t see anything wrong with what you’re doing.

 

[thatbus]

I figured it was something like that. Looks clean and a little lighter. Might be able to make something with a bearing press and a torch, but I don’t see anything wrong with what you’re doing.

yeah, if I was doing more than a few of these and selling 'em, I'd do it with a press, but I think my option is good enough for one pair.

Real happy with how this turned out. Especially for my first time ever doing this sort of stuff lol.

 

[Levigarrett76]

NICE

 

[thatbus]

NICE

Thanks man!

Big guy is done and just needs paint. Curious how much it weighs, think I have a load cell somewhere...

Hammer form for the final two parts; the aluminum seal retainers:

Sized up the wheels too. Got the centers bored out nice and cleanly:

This axle has a 77" WMS now. If I put an adapter plate on the "inside" of the wheel, I end up with 7.3" of backspacing to the inside lip, (4.7" to the outside lip). If on the outside; 9.5" of backspacing (2.5" to the outside lip). If putting the plate inside; is that too far from centered over the DRW hub, such that it will harm the bearings with 5000-6500lbs over this axle? Tires will be 385/65R22.5.

Any recommendations for paint? I have personally always had good luck with POR-15 and topcoating it with rustoleum tractor paint for something cheap-ish and durable. Any better options? Suppose I could always go with epoxy primer since I'd need that for elsewhere on the bus. I can needle scale but I have no intention of sandblasting this axle - not in the budget.

Thoughts?

 

[WaterH]

Nice job on seal retainers.

I think the Por15 and Rusto is fine.

 

[350TacoZilla]

Looking good man, only thing I would add is spend some time cleaning the seal mating surface. I've never had good luck with closed knuckle seals if there's any pitting.

 

[thatbus]

Looking good man, only thing I would add is spend some time cleaning the seal mating surface. I've never had good luck with closed knuckle seals if there's any pitting.

Thanks man. When you say you didn't have luck with the closed knuckle seals, was that keeping grease in, or keeping crap out, or both? What grease were you using - the "cornhead" stuff or something different?

Reason I like these is mostly to keep sludge/brine out during the winter. I have the non-greasable Ujoints so the only lube I really need is a little bit for the bottom kingpin bearing. As long as I can keep crap out, I'm happy.

I wonder if Rockwell 2.5T boots could be fit on these axles?

 

[350TacoZilla]

Just for simplicity I always heard the sealing surface on the closed knuckle style called bells or balls so I'll stick with bells. When I first replaced them in old D44 front it was pitted up and they only lasted a few outings before I saw grease leaking, took apart and found the seals chewed up with sludge of water and dirt in grease. I replaced them again and just continued (18 yr old at this time and just wanted to get back to wheeling) and within another month I saw grease again so I spent few hrs cleaning them up and using wire brush then sand paper to smooth them as much as possible and it seemed to fix the problem but I got rid of the truck not long after that. Just seemed like the seals were dragging over the bells and any small pit was a chance for the grease to escape and dirt to get in. I had an old scout that was same way when I got it so I cleaned them up and new seal seemed to fix it.

When I was building my truck with the 2.5T GMC axles they take over a tube of grease per bell so I smoothed them before assembly while the axle was out of stands and it was way easier obviously lol. I ended up selling those too before the truck was ever on rd so no idea how they held up.

 

[thatbus]

For anyone familiar with these Dana 70 front axles: do the original axle seals work with D60 shafts? Any first-hand experience?

I am running Chevy KP D60 shafts in my axle, 60 inner seals do not fit (wrong OD; D70 housing bore is 2.988"). From the only spec I've been able to find online, the Spicer 37275 seal meant for the D70 front has the correct OD but too large of an ID, at 1.57" - my shafts measure 1.562" at the seal area. Is the measurement of 1.57" nominal; is it the "correct" OD of a mating shaft's seal surface, or is that the exact ID of the seal and thus too large for my shafts?

Assuming this 37275 seal does not work, SKF 15241 or National 450326, 471958 should work, right?

 

[thatbus]

Axle's done. Very happy with it.

Only question is I may have drilled the 3/4 stud holes in the housing off a bit. They lean in 2° or so - is this a big deal? Or fine once I tighten em down?

Solved the seal issue by just machining a 1/2" thick puck for standard D60 seals. For anyone wanting to make their own; started with a 3" OD 2.5" ID tube. Dimensions were 0.500 length, 2.993 OD, 2.623 ID bored 0.400 deep (so the seal could seat against something).

Anyone here familiar with Sweet servo valves? Am I correct that pressure leaving the valve is about the same as pressure entering it? Therefore the pressure leaving it is high enough to use for my hydroboost and the following would work, right?

• Blue rectangle is reservoir
• Blue circle is pump (4.5 GPM)
• Pink is 3/4" suction line
• Green is 3/8" pressure line
• Red is 1/2" return line

 

[aczlan]

Anyone here familiar with Sweet servo valves? Am I correct that pressure leaving the valve is about the same as pressure entering it? Therefore the pressure leaving it is high enough to use for my hydroboost and the following would work, right?

• Blue rectangle is reservoir
• Blue circle is pump (4.5 GPM)
• Pink is 3/4" suction line
• Green is 3/8" pressure line
• Red is 1/2" return lin

Check with the manufacturer on your servo valve, in many cases the port marked "tank" has a limit of something like 300 PSI and is not intended to be used for power beyond (which would be what you're doing in this case).
Edit, looking up there plumbing diagram for a Sprint car, they show the tank line off of their power steering rack going directly to the tank and the additional valve to control the wing being before the steering, based on that unless they say differently I would bet that there is a pressure limit on their tank port: https://sweetmanufacturing.com/uploads/files/Sprint Steering Plumbing Diagram.PDF

Additionally, you don't want your steering to be restricted if you're stomping on the brakes.
If there's only a pressure in and a return to tank out port your power assist/power steering will be reduced unless the out line is unobstructed.
If your hydro boost is downstream of the steering valve, when you are stomping on the brakes the fluid leaving the steering valve will not have any place to go until build enough pressure to overcome the resistance of the amount of force you're using from the power boost before you can steer.
Let's say you run a 1500 PSI pump, if your hydroboost is using enough flow to create 500 PSI of back pressure, that means you'll have 1000PSI worth of steering assist available, but to use it you'll have to overcome 500 PSI of back pressure.


Aaron Z

 

[WaterH]

On my truck, the pressure goes to the hydro boost first and on to the steering. Not sure if brakes takes away from steering, but it obviously is not bad since I haven’t noticed it in 20k miles. Probably in a racing application, it could be a problem.