Drum to Disk conversion brackets, plans included
11-02-13, 02:03 PM
#1
Drum to Disk conversion brackets, plans included
I was going to just get RE-Speed’s brackets, but then they started taking people’s money without delivering parts, so I designed my own. The calipers, rotors, and parking brake cables I got from another forum member.
Per Fred Puhn’s Brake Handbook, I made the brackets out of .5” thick 1018 steel. It’s thicker than what I’ve seen other people using, and Puhn was writing about full on race cars, but this should definitely not flex.
The caliper needs to be spaced .19” away from the bracket. Instead of cutting down a huge amount out of a plate of steel, I used a separate 3/16” (.1875) piece. For both pieces I used cold rolled plate for its flatness and not cutting out all that metal would preserve the hardened layer.
Caliper and spacer shown.
If anyone wants a 3D step file or similar CAD file, PM me.
For the bearing retainer, I cut down the stock drum brake backing plate to a little square.
Another little bit I had to make was an angle piece to hold the brake hose to brake tube.
A post in this thread said to use 51” and 30” brake lines, which I found at a local parts store.
Done! So far, I've driven about 100 miles on it. I think it needs more air bleeding, but it's feeling good.
The biggest source of trouble I had with the install was the parking brake bracket on the caliper. Due to the thickness of the caliper bracket, it interfered with the nuts holding the bracket. I had a thick spacer in my bolt box that placed it out of the way.
Other notes:
A while back I did I brake job on a 1999 Civic and I noticed the rear disks are almost the same diameter and thickness, at least according to these Centric sheets. I think someone here could take these drawings and make an adapter to fit Civic calipers, several other Honda cars used that same disk. Only issue would be the parking brake cable, but a track car wouldn’t have one. I thought about it, but already had the RX-7 brake parts.
Last anecdote:
Before cutting metal, I cut out prototype brackets out of plastic, but only test fit them on the passenger side because testing meant taking off the drum brakes and pulling the axle. Once I made one that fit and cut a pair out of metal, only to discover the driver’s side upper link attachment was in the way of the caliper. It would fit, but no way could it slide. As far as I know the upper links are the same on both sides, and I doubt the whole axle housing could have twisted. So that was a plate of metal wasted.
Per Fred Puhn’s Brake Handbook, I made the brackets out of .5” thick 1018 steel. It’s thicker than what I’ve seen other people using, and Puhn was writing about full on race cars, but this should definitely not flex.
The caliper needs to be spaced .19” away from the bracket. Instead of cutting down a huge amount out of a plate of steel, I used a separate 3/16” (.1875) piece. For both pieces I used cold rolled plate for its flatness and not cutting out all that metal would preserve the hardened layer.
Caliper and spacer shown.
If anyone wants a 3D step file or similar CAD file, PM me.
For the bearing retainer, I cut down the stock drum brake backing plate to a little square.
Another little bit I had to make was an angle piece to hold the brake hose to brake tube.
A post in this thread said to use 51” and 30” brake lines, which I found at a local parts store.
Done! So far, I've driven about 100 miles on it. I think it needs more air bleeding, but it's feeling good.
The biggest source of trouble I had with the install was the parking brake bracket on the caliper. Due to the thickness of the caliper bracket, it interfered with the nuts holding the bracket. I had a thick spacer in my bolt box that placed it out of the way.
Other notes:
A while back I did I brake job on a 1999 Civic and I noticed the rear disks are almost the same diameter and thickness, at least according to these Centric sheets. I think someone here could take these drawings and make an adapter to fit Civic calipers, several other Honda cars used that same disk. Only issue would be the parking brake cable, but a track car wouldn’t have one. I thought about it, but already had the RX-7 brake parts.
Last anecdote:
Before cutting metal, I cut out prototype brackets out of plastic, but only test fit them on the passenger side because testing meant taking off the drum brakes and pulling the axle. Once I made one that fit and cut a pair out of metal, only to discover the driver’s side upper link attachment was in the way of the caliper. It would fit, but no way could it slide. As far as I know the upper links are the same on both sides, and I doubt the whole axle housing could have twisted. So that was a plate of metal wasted.
11-02-13, 06:57 PM
#5
Very nice job. As was said before, thanks from making the drawings available. Maybe someone like foxed.ca wouldn't mind hosting them.
I have a complete front & back unused BBK from Re-Speed. I don't know anything about the CAD programs, but if someone wanted to make a CAD of what I have I'll help where I can.
11-03-13, 03:39 PM
#6
I see the images so something is going on with his computer.
Very nice job. As was said before, thanks from making the drawings available. Maybe someone like foxed.ca wouldn't mind hosting them.
I have a complete front & back unused BBK from Re-Speed. I don't know anything about the CAD programs, but if someone wanted to make a CAD of what I have I'll help where I can.
Very nice job. As was said before, thanks from making the drawings available. Maybe someone like foxed.ca wouldn't mind hosting them.
I have a complete front & back unused BBK from Re-Speed. I don't know anything about the CAD programs, but if someone wanted to make a CAD of what I have I'll help where I can.
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11-04-13, 07:44 PM
#9
^^ I've done many old school RX-2/3 rear disc brake conversion from 81-85 gsl. you can keep the non-gsl rear "wye or tee". as far as the hardline, you can use the factory line, shorten it and double flare the ends using the 81 and up brake line fitting OR you can buy a new 3/16 hard lines from partshouse.
11-04-13, 09:56 PM
#10
The brake tees I found have a flare seat that wasn't compatible with the male end of the stock GSL hose. My plan was to use the drum brake's double female ended hose connected to a short piece of tubing that would then connect to the tee. The hose connection would have been clipped on to a piece of sheet metal that the tee would also have been bolted to.
RX-7s have a ridiculous set up where the rear axle has one pipe that goes from the front to the left wheel cylinder and that has a pipe that connects to the right side cylinder. The only bleeder nipple for the rear is on that right side (probably reversed for right hand drive).
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