The Stovebolt Site Forums The Parking Lot Big Bolts Disk brake conversion.. in progress...(1936 truck)

Some of you may be interested in what I am currently working on for my 1936 1.5 ton axle.

I am using gm 6 lug components.. which is the same pattern as the old drums

I started with rotors from a escalade/tahoe..(they are 12" rotors) and turned the bore diameter from 3.125" to 3.8" this allowed the rotor to fit over the hub..

http://i385.photobucket.com/albums/oo291/mack1416/Brakestop.jpg

I then reversed the studs that were used to mount the drum.. I am using 3 tapered lugs and 3 nuts with locks to mount the rotor. The tapered lugs will insure that the rotor is perfectly centered.

Then I picked up these massive calipers from a police addition tahoe... they are dual piston...

You can see in this shot that the rotor is bolted on as well
http://i385.photobucket.com/albums/oo291/mack1416/Calipershot2.jpg

http://i385.photobucket.com/albums/oo291/mack1416/Calipershot1.jpg

Next step is to fabricate some caliper brackets...

These brakes are going to be a necessity with the highway speeds I am planning.. some of you may remember the rear end conversion i did on my truck...

So far this brake conversion has been pretty painless..Ill keep you guys in the loop

Very nice. I really like the 12" rotor. Great use of off the shelf parts. Only one question: Is that big caliper going to clear the axle when the wheels are at full lock? Maybe it's the perspective of the photo.

SimS

Are those the stock '36 spindles? It sure looks like a clean way to update your stopping power. Very nice.

Sims... still working on the clearance.. i think it will clear but i wont know for sure till i put my axle back together...(hopefully tonight) im going to make some quick brackets and see if it does if not I will go to the smaller calipers which will give me more clearance

Canuck... Yes those are the stock spindles

If you have problems with clearing the axle it looks as thought you may be able to flip the rotor over and push the calipers mounting further into the wheel as long as it will clear the wheel???? This is a promising looking piece of work I am going to be looking at the possibilities of doing this with a little bigger brake set up after seeing this. Good job!!!

Nope... Can't flip it... Unless you wanted to then space it back out some... The rotor will fit flipped but barley definitely no room for the caliper... These were the biggest rotor/caliper combo I could find with the right hole pattern... Except for the aftermarket big brake set ups for the guys running 24-26" rims... You can get kits with 15" rotors and 6 piston calipers but these kits run over 3,000 dollars... So far I'm in 300 in parts... And would have been 70 less had I had cores to exchange when I picked up the calipers... Probably 50 more less if I went with the single larger piston calipers

CORPO, if the caliper hits the front axle, couldn't you mount it above or below the king pin, instead of in back or in front of the king pin?

Paul.

Well i think i have issues with the turning radius, i have to reassemble my axle to check for sure... reamed out my new king pins last night.. so assembly should be good for tonight

So yes i can move the calipers to the top, I was hoping to avoid this due to the location of the bleeder. (the bleeder always need to be to the top) for proper bleeding. Worst case if i put it at the top and it doesn't bleed properly I will have to unbolt one of the mounts and stand up the caliper for bleeding

Ill get it worked out...

Well things are looking up for this conversion.. I made some quick brackets they are off a bit but i was able to hang the caliper and swing the steering

Ignore the bolts hanging out.. only M14's i could find on short notice
http://i385.photobucket.com/albums/oo291/mack1416/Brakeshanging1.jpg

Here is full lock making a left turn. I hung the calipers to the front
http://i385.photobucket.com/albums/oo291/mack1416/Brakeshanging2.jpg

Next is to finalize the brackets and make them extra beefy.. im thinking i am going to double up 1/4" plate.. and then maybe add some ribs if there is clearance

Does anyone have an extra steering stop? One of mine is missing.. let me know

CORPO:
That is looking great you may have started someting here the next Big Bolt brake trend.
I have a stearing stop from a 56 1.5 ton it might be the same.

That setup looks fantastic! My question is this- Is the rest of the stock front end going to tolerate all that stopping power? I guess I just assumed that 74 year old steering and other bits would not be worth driving at highway speeds. Will the stock front end be as nice to drive as say a modified more modern one?

I'm thinking of what to do with mine.

This is the steering stop i am looking for
http://i385.photobucket.com/albums/oo291/mack1416/SteeringStop.jpg

Little update.. i was having a difficult time getting the caliper placement just right. So i made some adjustable brackets by cutting apart my other attempt at brackets and put a spanner piece in between and threaded and tapped the holes. I then adjusted the placement, tightened the screws. Now i will remove them and transfer the holes to a fresh piece of steel and draw out a profile.

http://i385.photobucket.com/albums/oo291/mack1416/Adjustablebrackets.jpg



I beam style axles haven't changed much from what I know. The only real difference I am aware of is a more modern axle will have a roller bearing set up vs a ball bearing set up. I am going to look into swapping roller bearings into it, I wouldn't be surprised if I can order a roller bearing to fit in to it. As far as the steering and other components go, I dont see any reasons they would not work just fine. Its not going to run like a modern pick up truck, but im not expecting it too

If you want it to run like a modern truck, your best bet would be to do a full frame swap and just put your cab on a modern truck

Too me increased stopping power is good at any speeds. Unless you do something to your rear axle you wont have to worry about getting to highway speeds

Nope sorry the steering stop I have is for the most part a bolt.

Thanks for looking, im sure I can make one out of some steel plate if I cant get one..

CORPO, I have an extra steering stop, send me a PM with address and I'll send it no charge.

Looks great. Would you be able to mfg a bracket that ties the bottom and top bracket together as a single unit. I see you have the axle clearance issue to deal with so maybe not.

I've done the 12" conversion using Camaro rotors and PBR calipers on a 67 Lemans and 58 Chevy. With both of those I was able to mfg the bracket out of a single piece.

Clutchheadstew, That is very generous of you. I will send you a message



I think I can tie them together but im not sure I am going to. I am planing on doubling up quarter inch plate, I think it will be more than strong enough.

Hey CORPO is there anyway you could send me a outline on paper through email or post the deminsions on the bracket for the calipers. Im working on a 46 1.5 Chevy and having some trouble getting to fit bout to scrap the front and just put a solid axle. I f it not to much to ask. Thanks

ill see what I can do, I was planning on writing up how I did it once I was doing final assembly but thats still kinda in the future..

Well it been awhile since you came up with this conversion, how's it working?

Ever write anything up on the process? Additions over time, etc.

Truck is going back together now... Don't get a lot of time to work on it so its been a long journey... Everything is back on the axle assembly, working on plumbing the hydro booster... And the rest of the brakes ...

Hoping to get it on the road summer 2013... Keeping my fingers crossed...

Wow.. been a long time since I dug up this thread. I had a request for the caliper bracket patterns, So I thought I would add them here for anyone else.

http://i385.photobucket.com/albums/oo291/mack1416/Brake%20Caliper%20brackets_zps76ssszla.jpg

Truck is back on the road as of this summer, still debugging a few things, and trying to get all the backlash out of the steering box. At high speeds she is wondering a bit, and I just cant seem to get it all adjusted out.

She goes and stops no problems. Some of you may recall my truck but for those of you that don't she is far from stock. I picked up a truck that was destine for the scrap heap and managed to put her back together, by combining two cabs and lots of new steel. Besides the custom disk brakes, other notable items would be the custom 1 piece front rims and the custom rear axle with 3.07 gearing which mates to the old wheel pattern.

Anyway the brakes work great,the hydorbooster stops the truck like a modern truck, I havent pushed her to hard yet but I have had her up to 65 MPH and feels nice and stable except for the steering wander. I have recently changed out the tie rod ends, but I am thinking I need to redo a king pin again... Doesnt seem right.

Thanks guys, let me know if there is any questions on the brake design..

Heres a few of the truck (Im sure she wont be everybodys cup of tea)

http://i385.photobucket.com/albums/...2-4932-A3DE-7BB5DF307503_zps1a8x4klh.jpg

http://i385.photobucket.com/albums/...A-4EBA-B8F4-5EF40037FBB8_zpsjixphg14.jpg

http://i385.photobucket.com/albums/...2-4094-824F-543F1D31B301_zpshwmugftf.jpg

http://i385.photobucket.com/albums/...C-4DF2-A215-1942AD4F7BC0_zpsquxy0oka.jpg

CORPO,

I see your steering box is mounted inside the cab. Have you put a dial indicator on the frame and measured the cab movement when someone turns the steering wheel? If the cab is sitting on rubber pads there could be movement which could effect the steering...just a thought.

Also re-check the front end alignment, make sure you have some toe-in to help it track straight.

You're right, it's not my cup of tea...lol, but I love the work you have done, great craftsmanship...keep it up!

Mike B

Thanks for the input Mike... I have toe set to 3/16" in..

The movement I am getting is at the steering box shaft... I can move the wheel before any movement in the pitman arm... I have tried several different adjustments but can't seem to get it right. I am not 100% sure on the proper technique for adjusting the lash in the box.

It is the original box from the truck, so perhaps it is just to worn out

How far off of the floor did you take your 3/16" toe in measurement? The factory max toe in is 1/8", you might be a touch heavy, but not enough to worry about, just keep an eye on tire wear...

To adjust the backlash between the worm and sector you need to loosed the sector shaft housing bolts (4 of them) 1/4 turn and then rotate the eccentric bolt and nut to take out the play. Make sure you don't over do it as this will cause further damage to the steering gears.

Shaft end play is taken out by loosing the large lock nut on the side of the box and turning the slotted screw clockwise to take out the play.

Always proceed very slowly, it doesn't take much change to make a big difference. Adjust and check full travel of the steering wheel then, repete as needed. Also, all adjustements are made with the steering wheel centered.

Hope this helps.

Mike B

Mike-

I took the measurement at the center of the tires. I jacked up the front end.. spun the wheels and marked a line so I could use the same reference front and back of the tire..

Thanks for the info on adjusting the box, I definitely did not loosen the 4 bolts before adjusting the eccentric. My box has a small plate on the back with a slot that has a jam nut, I loosened the jam nut and slid the plate which seemed to change the back lash in the gears. However, I slid it to the end and still have some movement...

Im thinking I will have to take another look at these adjustments..

Thanks again

CORPO,

The adjustment I gave you is not for the box you have...

Send me a PM with your email and I will scan the adjustment proceedures for your box.

Mike B

would a setup like this be acceptable for my 1955 1.5 ton or is the rotor too small to work on a truck that will be going down the highway at 65-70mph with a load? If so, will this caliper bracket design bolt onto my truck or will I need to work on the design to fit?

Thanks, Richard

I don't know what your axles are, however, at some point modern axles with 14" brake discs make sense, Grigg has discussion here about modern front spindles on 2 ton front axle, P3500 HD have D70 and 80 rear axles with modern brakes, 5/10 on 7.25" bolt pattern.

Ed

I'm trying to keep the stock spindles and axle while just making a bolt on solution, the axle swap is a little too much for me.