Davidmij - Disc Brake Conversion & Rim Problems

[davidmij]

Hey everyone, So I finished the brake job on my 59 T-bird and everything went great right down to bleeding the brakes. However, I put the wheels back on and they just barely hit the calipers - when I tightened the lugs the wheels wouldn't turn. I looked closer and notice the wheel just barely touches the calipers (on both left and right wheels). I got one caliper from RockAuto and the other from Autozone. They're for a 1990ish S-10 Blazer 4WD, per the excel spreadsheet list.
Dave Dare, I think we ordered the caliper bracket for a 59 Galaxie because it was $10 less than the one for a 59 T-bird and it looked identical. You don't suppose there's a tiny difference we didn't see do you?
Anyone have any suggestions? It looks like I could grind the caliper case a tiny bit and make them work, but I thought I would ask around before getting crazy on it.

thx in advance, Dave Jones

[simplyconnected]

Dave, you have the right calipers, and everything is normal. Original wheels were never designed to fit over calipers. This is discussed at length in the Brake Conversion thread.

You need either 15" wheels OR 14" that went on disk brakes. The most popular wheel is the Granada/Mustang wheel. Howard Prout made a trip from Canada to test his 'new' 14" Granada wheels on my setup before he started his Squarebird. They fit on mine and they fit on his Squarebird. We both have the same spindles and calipers you have:



This is a 14" X 6" Granada wheel. Howard is holding a tape measure against the back of the spider to measure for back spacing. The front (on the LH side) shows the valve stem hole.
NOTICE, on the bottom of the wheel there is a bulge in the center-right. That is there for caliper clearance.

Squarebirds and '59 Galaxies use the same spindle. Therefore, the caliper bracket is identical. I am using the same Scarebird part on my car as Howard is on his Squarebird.

Notice, the Galaxie is using 15" Cragar SS wheels (to the left). They fit just fine. Howard had just bought a new set of 14" tires so he wanted to stay with 14" rims:


I had run my power disk brakes all summer long before Howard tried his Granada wheels. They probably look identical to yours only older, now:


So, don't grind ANY off your calipers, rest assured you have the correct brackets, and get new wheels designed for disk brakes. I understand the 14" spoked Squarebird wheels fit, too (but they are very expensive).

My '55 Ford Customline came with 15" x 4.5" wheels. For the heck of it I tried one on the Galaxie... it fit. - Dave Dare

[davidmij]

Thanks Dave. It's been so long since I went back to the thread I must have forgot. I've been referring to my notes I made when I read it months ago. For some reason I had it in my head that the granada wheels were only if you wanted to use salvage yard granada parts. This is not a real problem as I was going to change out the wheels anyway. Do you happen to know what style wheels (in 15 inch) will fit the 4.5" bolt pattern? I'll call around for some used wheels at the junk yards - this is just a RatRod project anyway. The rear wheels may have to be a little wider cuz I want to use cheater slicks. Guess I better start pricing those. Good thing I'm working OT this weekend again, I'll need some $ to pay for the wheels.
thx for all your help Dave Dare - I'd be totally lost without this web site and all the good members.

[davidmij]

Oh, I forgot.
the rod that connects to the brake pedal from the M/C doesn't have the same size "eye" hole as the original one. Thus, the eye in it is a little sloppy. Seems fine for my purposes, but I thought I would ask if anyone else had this happen? I'll measure it and get online to find a bushing to fit it.
- dave J

[Dakota Boy]

David, I also ran into this issue with the pushrod eye diameter.

I made a bushing which I then press-fit onto the eccentric bolt.

[simplyconnected]

...the rod that connects to the brake pedal from the M/C doesn't have the same size "eye" hole as the original one...

Your original rod used a shoulder bolt with an eccentric for adjusting the pedal rod length. The hole in your brake pedal is 3/8" and the original rod hole is 5/8". You also used nylon washers in that old rod which brought the diameter to 1/2" (the size of the shoulder bolt).

I believe you now have a new adjustable brake pedal rod with a 3/8" hole to match your 3/8" brake pedal hole. If you use a fine-thread bolt, the diameter should be right. Also, use a nylok nut because the bolt must pivot.

Many cars used 14" wheels on disk brakes: Ford, Mercury, Lincoln, Chrysler, Dodge, Plymouth. One of my old tire store buddies looked up (14" x 6" 5-stud on 4.5" centers) on his Hollander Crossreference books. He came up with a dozen cars that used compatable wheels. I think Ray has some in the Technical Resource Library. So, bottom line is they don't have to be Ford rims to fit our Squarebirds, but they do need to come from cars with disk brakes. Buy five.

Edit: I forgot to say, NONE of these wheels need spacers. I haven't found a 15" wheel that doesn't work (but make sure your front tire clears the fender when you go up driveway aprons). - Dave

[davidmij]

Thx dave, that's kind of what I've read today. I'm going to head down to the junk yard in Espanola this weekend and see what I can find on the various cars. My bucket seats were $15 each, didn't matter what car, year, condition, etc. Any seat in the yard was $15 - I gave the guy $25 for a pair that are almost brand new.
Hopefully I can find 2 wheels with tires in a 15 with 4.5 bolt pattern. The back ones will eventually be a special order cuz I want cheater slicks. I'll have to do some shopping around to get the cheapest 15 inch slicks I can find. Oh, and I'll get a 5th wheel for a spare.

[scumdog]

With all this talk about caliper clearance, has ANYBODY found alternative rims/alloy wheels that fit '66 Thunderbirds (and clear the calipers)???

[davidmij]

OK, I have another problem. (my on going brake saga) I found 3 wheels for my front and a spare at a Santa Fe junk yard. I then found a couple of roller tires at a local gas station and busted them by hand. One of the tires had a hole in the wall so I had to get another one. I forgot how much work it is do tires by hand! Anyway, I got her fired up and rolling but the brakes are not getting any power. It's like driving with the engine off. I remembered I had a vacuum line open at the wiper motor so I plugged it with a bolt. I basically have just the vacuum line off the intake manifold going to my power brake module. The rest are removed. I'm guessing that's not enough? I have no idea how vacuum lines power things. Can anyone offer advice on this?
Thx, Dave J

[davidmij]

new brakes don't work

OK, I have another problem with my disc brake conversion. (my on going brake saga) Anyway, I got it done and fired her up. The brakes seemed to work, but they are not getting any power. It's like driving with the engine off - super hard to stop. I remembered I had a vacuum line open at the wiper motor so I plugged it with a bolt. I basically have just the vacuum line off the intake manifold going to my power brake module. The rest are removed or plugged. I'm guessing that's not enough? I undid the vacuum line to the brakes and it stalled out. I managed to hold my finger over it while my son started the car and it has a good amount of suction, I actually have to pull my finger off the tube. I don't know how much it actually needs or how to measure it. Here is my M/C, I used the front fitting (the one on the end) for the front brakes. http://cgi.ebay.com/ebaymotors/ws/eB...AQ:MOTORS:1123
I used this proportioning valve: http://cgi.ebay.com/ebaymotors/Ford-...Q5fAccessories
I hooked it up the way "Simplyconnected" shows in his picture of this valve. Does that look right Dave Dare? Oh, another thing to mention - after I turn off the motor and press the brake pedal for the first time, I hear the air suck back out of the power assist module. In other words the brake pedal releases the air - it holds pressure like it should. Does that make sense? I don't always convey in writing just exactly what I'm trying to say.
Can anyone offer advice on this?
Thx, Dave J

[simplyconnected]

Yes, it sounds good so far. You have vacuum, you used the larger reservoir for your front lines, you connected the prop valve according to the diagram, and your booster holds a vacuum even after your engine stops (so you still have power brakes in an emergency).

Run some tests:

With the engine off, disconnect the top pin. Does the booster return all the way to the 'at rest' position (or is the linkage pulling it in)?

Have someone step on the pedal with the engine running, and WATCH the linkage. Does it bind? Does it hit the end of its stroke before the brakes lock up?

If it all looks good, the next part I would look at is the space between your booster and your M/C. (This isn't your brake pedal rod... that's another thing.) How much gap is there? You can measure this without disconnecting lines. If you need to, use a piece of clay or plumber's putty because everything is hidden.

All these vacuum-powered booster systems work the same and they are pretty easy to set up. There are no secrets and there shouldn't be any surprises... step on the pedal, booster opens a vacuum valve which adds assist to your master cylinder.

Hey David, did you take any pictures???

[davidmij]

No, I used the front, (small) reservoir for the front brakes, and the large one for my rear brakes. That's probably the problem.
I'll switch them and see what happens. I'll post some pix too, I always get caught up in the work and forget to take photos as I'm working.
Just to be sure, I need the small reservoir to go to the rear and the large to go to the front???

thx, Dave

[Astrowing]

Yes, the larger reservoir is for the front disks. They have the much larger pistons so more volume of hydraulic fluid is needed to move them.

[davidmij]

I'm sure that's the problem then. I'll have to get air out of the lines once I switch them too. Bummer, bleeding is a lot easier with the car on blocks and the wheels off.
thx Jim.

[RustyNCa]

With all this talk about caliper clearance, has ANYBODY found alternative rims/alloy wheels that fit '66 Thunderbirds (and clear the calipers)???

If you don't mind the look, I am pretty sure the late model Mustang Bullit rims clear.

I tried them on our 65 and I am pretty sure they would clear without running a spacer. I am running a 1" spacer in front, but I remember thinking at the time, they would clear without it.

The rims are 17" so that may not give you the look you want.

For an idea, the front tires are 245 the rears are 275. The car is also lowered at least 2" probably a bit more in front and 2" in the rear also. Actually in that photo I might not have the back lowered yet.

Cheers
RustyNCA