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Cheap Big Brake upgrade

17K views 57 replies 9 participants last post by  X-77 keith 
#1 · (Edited)
Doing this right now on a 68 El Camino. Same principles and parts as drum brake first gen Camaro.

I bought a disc brake booster and mc for ridiculous cheap on CL. Brand new MC with lifetime warranty. The guy put it on his 68 Chevelle and his fancy wheels wouldn't fit, so he bought a complete Wilwood kit.

Cheap Big Brakes

Very straight forward following the guidlelines set out on David P's web site.

Wanted to ad that you will need to source a new bolt for the top of the bracket. The drum brake bolt doubles as the anchor pin for the drum brakes.

Also wanted to ad that if you find a set of backing plates cheap (I did.... they came with the used 69 style caliper brackets I am modifying... paid $80 free shipping for caliper brackets AND backing plates) you can use the 69 Camaro or Chevelle dust shield. You just need to make a lot of cuts along the perimiter to flatten it out just a bit. If you aren't worried about looks (who is going to see your dust shield anyway?) it works just fine.

One other thing; I didn't see this in the write up, but just to make sure everything fit perfectly, I had the "additional" metal drilled an bolted to the spindle before tacking the caliper bracket in place. Then took it back to the bench to make sure everything was square and lined up perfectly. I didn't want to have to wallow out the bolt holes even a little bit. Everything fits tightly that way.

Also, when you order calipers and brake hoses, don't forget to order two banjo bolts (I didn, so now I have to wait a few days to get this on the road).

Now, if I can just find someone with a mid 70's Buick or Olds with 11 inch rear drums they are parting out..... I would be set. Plan to use the El Camino as a tow vehicle from time to time, so that is why I went with the Corvette front rotor and truck calipers.

MANY THANKS TO DAVID POZZI FOR POSTING THIS PROCEDURE. I will have less than 1/3 of the cost of aftermarket brakes, and it will be serviceable with all GM parts.

This is a really fun procedure if you can do light fab work and have a good welder. I did not send the spindles to be machined. I measured carefully and cut it with a hack saw, cleaned it up with a large file. Hey, I needed the exercise anyway, and this is better than the gym. Plan on wearing out a good Lenox hack saw blade per side before it is all said and done.
 
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#2 ·
Awesome! So much of this hobby has devolved into buying Lego kits and snapping them onto a car. Great to hear about your project. I don't envy you sawing off the bosses with a hacksaw!

If you don't need an internal parking brake, it may be just as easy to fit calipers on the rear as it is to upgrade the drums.

I finished up a scratch built JL-8 system and while it was a pretty challenging project, the braking performance is phenomenal and I have a lot more faith in GM parts vs. aftermarket consumer stuff.
 
#5 ·
I finished up a scratch built JL-8 system and while it was a pretty challenging project, the braking performance is phenomenal and I have a lot more faith in GM parts vs. aftermarket consumer stuff.
What did you do about caliper brackets? Did you buy a set of stock JL8 brackets? That has been the big hold-up for me - even the reproductions are ridiculously expensive.
 
#4 ·
Pictures, or it didn't happen! :p

I am really interested in this. I also read David's article, although he said this was just a mockup, and he never actually got it working on a vehicle. I will be looking forward to reading about your results.

Could you accomplish the spindle modification with an angle grinder and/or a sawzall?

Wouldn't the 11-inch rear drums also be on the mid-70's Caprice Classic and full size station wagons? What about pickup trucks?
 
#6 ·
I found the caliper brackets with backing plates on ebay a few months back. You have to modify the standard bracket as set out in the article to move them out 3/8. They come up from time to time.

Yes, most full size Chevys of the mid 70's have 11 x 2 rear drum brakes. Don't know why I said Buick or Olds. The Chevy rear brakes would work fine.

I will take pics tonight if i don't forget.

Could you accomplish the spindle modification with an angle grinder and/or a sawzall?
Yes you could. I have gotten pretty good with a hack saw on stuff like this. Just took about 5 minutes to cut off. Angle grinder would sure create a lot of metal dust!
 
#8 ·
I have a buddy that works at a professional welding shop that does a lot of fabrication. If I decide to take on this modification, I will probably tack weld it and run it out to him for the final welding, just to be safe.
 
#11 ·
Sounds awesome, Lynn. One thing that interests me about this upgrade is that you get all the advantages of the larger rotors without moving the wheels outboard as far as the factory disc rotors will do. Looking forward to seeing those pics and hearing about your results!
 
#13 ·
Hey David,

The pictures of the caliper bracket appear to show the metal plates that were used to relocate the bracket 3/8" further out to be welded on the face of the bracket. In other words, it looks like it will space the brackets inboard by the thickness of the plate, unless some type of spacer is employed. Am I seeing that right, and if so, does it cause any issues with caliper / rotor alignment?
 
#14 · (Edited)
They need to be flush on the spindle face, and I think they are pretty close to that but it's hard to see, maybe it was built up with weld. You don't want to move the bracket in or out. Just outward radially 3/8" to compensate for the 3/4" larger OD rotor.
 
#15 ·
I agree, the above pics make it look like it was just welded on top.
I cut out metal and inserted 1/4 inch thick tabs in the opening.
First cuts were made with the hacksaw (really starting to hate that thing.... hmmm, may be time to by a big time band saw) and the side to side cuts were made with a sabre saw on very low speed. Still wore out a few blades.

Not many pics tonight. I have a very complete write up almost ready to go, but left it on my computer at the office. Tomorrow nite wiill be more complete, and I will answer more questions. Did get the booster and new master fitted tonight. Have to buy a new brake line from the master to the distribution block. Old one isn't long enough. As you can see, this is a GS (grimy sucker). It is a driver. The old engine leaked oil from everywhere. I didn't even bother to clean up parts when I rebuilt the front suspension.
 

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#16 ·
Looking good, Lynn. I think this is the direction I am going to go on my 67. I am thinking that I will make my inserts with the new holes ahead of time, and then make up a jig to mount the bracket on and use the inserts to scribe the metal that will be cut out of the bracket.

A thought crossed my mind - can the same thing be done with a set of 67/68 caliper brackets and then mount a set of the C3 Vette calipers on those? I already have a set of the 67/68 brackets, and C3 calipers are pretty easy to find. The only catch I can think of is that there might be some offset issues going from the stock rotor location to where the Vette rotor would end up mounted on the drum spindles. The same issue may be present with the single piston caliper, but that is a sliding design that might be able to compensate for this.
 
#18 ·
So, guessing you all know what drum brakes look like.
Here is the before shot.
As you can tell, this isn’t a resto. This is a driver. When I rebuilt the front suspension, I did not worry about cleaning up the parts. The old engine & trans (307 PG) leaked profusely, which is one reason the vehicle is 99.9% rust free. Oil everywhere. PS box still leaks, but will get replaced soon.

This is a 68 El Camino. However, everything will be the same on any drum brake first gen camaro.
Probably not worth doing this to a disc brake car, as the factory disc brakes are good enough for street cars. However, those parts are getting hard to source, so this works out pretty well going from drum to disc.
 

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#19 ·
So, here is the spindle in the vise. You can see the boss that needs to be shortened. Notice the first ½ inch of the hole is not threaded. The alignment anchor pin for the drum brakes goes in this hole and has a shoulder that fits tight in the unthreaded portion. I believe David’s article says to remove .610. I did that on the left side, and it worked out perfectly. Just to check, I bolted the caliper bracket in the boss (before shortening the boss) and measured the gap between the bracket and the lower mounting hole (which doesn’t get shortened. I used a snap gauge (you can barely see it in the last pic). And put a mic on it. .607. So, are we really off .003? I doubt it. These brackets are just stamped steel. We aren’t setting ring gaps. The MAIN thing, in my opinion, is to make sure the brackets stay square to the spindle. It is a floating caliper, and will auto adjust for a few thou either directions. What it can’t do is square itself.
 

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#20 ·
You can see the boss to be cut off in one of the pictures above. Measured .610 and scribed it. I intentionally cut off a little less, so that if I did not stay perfectly square, I could square it off with a grinder or file. Fortunately, all I needed was the big a$$ file. I really wasn’t worried about taking off a little too much. It would be very easy to shim it out. I did not need shims on either side. You would have to fubar it pretty badly to ruin it.

About 80% cut through. Looks daunting, but I timed this one. Even with the break for photos, it was 7 minutes. Way shorter time than a trip to the machine shop.

Fist thing is to bolt the bracket (unmodified) into the existing holes and make sure your bracket isn’t bent. Take careful measurements. I measured both holes from the caliper alignment tab AND each hole from the mounting pin threaded hole. As pointed out in David’s article, you want to move the two mounting holds 3/8 farther out (or depending on how you look at it, 3/8” further in). The point is to get the bracket 3/8” farther out so that the big truck caliper will fit and not hit the rotor.
 

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#21 ·
I already had two “tabs” that I made the night before. ¼ inch steel stock.
When cutting tabs for the left side, I just made two additional ones. They are mirror images. Vise grip the tabs to the bracket, and measure multiple times for where you want the new holes. I then scribed an “X” where I thought the holes would be. I then scribed around the tabs to cut out a corresponding area for each tab.

Set the tabs in the bracket and measure again, making any adjustments needed to get the holes right where I wanted them. Once satisfied with the hole locations, center punch and drill. The upper hole is exactly 5/8 inch; the lower ½ inch. Seems it is getting real hard to find decent drill bits lately. I have two sets of Norton bits, one for softer metals and one for the really hard stuff (HSS). The softer ones wear out with one use, and the harder ones are so brittle that I keep breaking them. I drilled ¼ inch pilot holes and then use a step drill to complete. With step drills, even the cheapo ones seem to out perform standard bits. I used this one A LOT doing an engine & trans swap on my 49 Studebaker farm truck over the winter. It is still cutting. Of course, the ¼ inch steel is thicker than the step, so once you get to the desired size, you have to turn the piece around and hit it for a few seconds to get the hole all the way through.

I drilled the holes before welding, just to make sure it would fit. I didn’t want to have to wallow them out. The tighter the better. Mocked it up and took it over to the welder for tacking. Good thing I did that. While mocking and moving things around, I apparently flipped the upper tab, and could immediately see the caliper was too close to the edge of the rotor. The top locating pin just touched the rotor, while the bottom one had plenty of clearance. I immediately knew what I had done. Get out the die grinder and cut the tack weld. Ground it smooth and flipped it around. Perfect fit.
 

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#22 ·
Here it is all together (at least what I have). When I ordered calipers, I thought I got them “loaded”. Apparently not. Waiting on pads as well as banjo bolts for the hoses.

Didn’t take any pics of the stud replacement. Dorman number is DOR 610-157. You might be able to get by with your original studs if you are running steel wheels. I have old school Centerlines (the old, old ones that have the hub caps attached with screws) and they are considerably thicker, so the old studs were just barely long enough BEFORE replacing the drum with a rotor.
 

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#24 ·
Got the booster and master mocked up last night.
I bought a master cylinder and booster locally on CL. The master is brand new and comes with a lifetime warranty. The guy had a disc brake Chevelle and bought all new parts (except the booster, which is used) and spent huge $$$ on some wheels that would not fit over his four piston calipers. He ended up buying an aftermarket brake kit. He had already sold his four piston calipers, spindles and rotors, or I probably would have purchased all of it from him.

The brake line from the front of the mc to the distribution block was now too short. I came home this evening planning to pull the line and head to the auto parts store for a replacement. Got the line off, and realized the two small hard lines from the flex line to the drum brake wheel cyl are the same size as the small end. The first shot below shows one of the left over lines already attached to the valve. The other left over line is sitting just below for comparison.

David recommended a Wilwood adjustable proportioning valve, part number 260-8419, which I had already purchased and had on hand. It also takes that same size flare nut (after screwing in the adapters that come with the valve). So, how fortuitous was that? I took some bends out of the small line, hooked it all in line with the adjustable proportioning valve, and everything fit without having to buy more parts. Screwed two holes in the fender well and mounted the valve on the inner fender. Instructions on the valve say that with the valve screwed all the way in, there is no restriction. I will start there, and adjust accordingly. Tried to take a couple shots of the adjustable proportioning valve, but it is really tucked in there. I don't have to worry about it getting dinged from some foreign object from underneath.

I believe I ordered flexible brake lines for a 69 Camaro. I am not sure they are long enough. I may have to slightly relocate the end of the hard line. Will know next week.

I went ahead and bolted the front wheels back on so I can move this over the weekend. Have to re-arrange cars in the garage this weekend. Will have to be careful and use the e-brake!!!!

This is as far as I can go without the banjo bolts and the brake pads, which should be here monday.
 

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#25 ·
A note about brake hoses. The drum brake Camaros have hose anchor points on the side of the frame rails. The disc brake cars have them on top of the frame rails and the hose runs along the upper A arm and attaches to it with a bolt. I used a hose from a 72 Monte Carlo on my 67 Camaro, the discs came from a Monte in a wrecking yard. If your hoses attach to the top of the frame rail, then they need to be 69 type.
 
#27 ·
David, my 67 has drum brakes and still has the drum brake hard lines. Should I leave those and use the Monte Carlo hoses, or switch to the 69 disc style? I have both available.

Also, I found that the stock 69 Camaro style single piston caliper brake hose boss will interfere with the A-arm bump stop on a 67 subframe. I think your article mentions this too. The Chevelle / Monte calipers have a lower hose mounting boss and will clear. Do the big truck calipers have the lower brake hose mount, or is it on top like the Camaro caliper?
 
#28 ·
I had Monte Carlo calipers on my 67, the banjo bolts hit my bump stops. I would convert to a 69 bump stop on the front side of the A arm. You will need to weld on a small subframe plate to contact it.

It was a long time ago, so I think I used Monte Carlo hoses, but I could be mistaken. I think the 69 setup is better/ easier on the hose. The frame rail side makes the hose twist more, the 69 version bends it, if that makes sense.
 
#29 ·
That's odd - I installed a set of the Monte Carlo calipers and they actually cleared the bump stops on my 67. That was with a custom caliper bracket that was sold through Rick's, however. It might be a slightly different location with the GM brackets, so I guess I will have to mock it up and see.
 
#30 · (Edited)
Well, I feel like a retard. I had the adjustable proportioning valve in line in the front brake line, instead of the back.

Fortunately, I realized it before installing the master and bleeding the system. Don't know what I was thinking.

Took it all apart, and put a 3/16 flare nut union in there, so i was able to still use the original line with the small hard line attached. But... that meant I needed to have different adapters for the proportioning valve to put it in line with the rear. It comes with two fittings 1/8 pipe to 3/16 flare. I need 1/8 pipe to 1/4 flare. Went by O'Reilly's and they didn't have anything like that. The local Ace Hardware probably does, but they close at 6:00 pm. Life in a small town.

Stay tuned.
 
#32 ·
I have a very strange issue. Got the brakes bled, took it for a test drive and everything was perfect. Stopped nicely. No panic stops, because I wanted to bed the brakes in gradually.

Anyway all was good, until I started to back into the garage. I had to turn the wheels hard to back in and something started dragging. Took it to a vacant parking lot and any time I am backing up with the wheels turn almost full turn, it drags to a halt even without my foot on the brake. Put it in drive, and leave the wheels cocked and it goes just fine. Put it in reverse, back up straight and it is fine. Turn the wheels and it grinds to a halt. Tires, wheels, calipers are not hitting anything, and the flexible line is definitely not in a bind. I even had Sherri back it up slowly, turn the wheels until it started grinding, and crawled under the front with a flashlight to make sure everything was clear. I can hear the noise from the front wheel area. Just can't see anything rubbing.

I haven't pulled it apart yet to see what is rubbing, but something is. Seems very strange it would only rub in reverse with the wheels cocked. And I am not even applying the brake. I should have some time tomorrow evening to check it out.

Don't like giving bad reports, but if I can help one of you avoid whatever mistake i made, then I figured I best give the whole story... good bad and ugly.
 
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