Curtis in MA
Senior Member
I welded up my rear roller tracks and need to grind them flat. What do I use? A straight file?
Weld and grind roller tracks
- Thread starter Curtis in MA
- Start date
Steve Plucker
BANNED
Putting reproductions in in place of the originals...Probably softer metal???
Pluck
Pluck
160B
Well-known member
Scribe a cut off line.
I used a Dremel rotary with a thin cut off wheel, takes a steady hand cut slow and keep the RPM mid range to help keep a straight line, be patient, you will break a few cut off wheels but I was very pleased with the result.
whirnot
Well-known member
I just finished mine using a 4 1/2 grinder with a cutoff wheel. Marked the cut line and cut off the excess weld to near the mark. Then used the cutoff wheel like a grinder and carefully ground to where I wanted it, measuring often. Worked fine. The wheel makes a nice flat grinder.
Drive Shaft Dave
Well-known member
It is more of a hassle to replace them , weld then file or use die grinder.
Purdy Swoft
Well-known member
I used a small thin cut off wheel on mine . Replacing the brake tracks doesn't automatically center the brakes , I would probably have to go back and either grind or weld and grind the new tracks to center , I think that it is easier to weld and grind the original tracks in place .
Bill, Dave, purdy ,
I agree entirely it is much quicker, less expensive , and easier to weld and surface them Than to replace them.
You can use a mill or the 4 1/2 inch die grind cutoff wheel does well to. I have a gauge I use that fits from the pins to the correct stock track surface dimensions to check the location. Once to the correct dimension and shoes are arced and installed you can check with a brake centering gauge.
You must be careful using the back edge of the cutoff wheel but it can be done for those who don’t have fancier equipment. As always use proper eye protection
I do a lot of brake work and am usually repairing tracks every week.
Larry shepard
I agree entirely it is much quicker, less expensive , and easier to weld and surface them Than to replace them.
You can use a mill or the 4 1/2 inch die grind cutoff wheel does well to. I have a gauge I use that fits from the pins to the correct stock track surface dimensions to check the location. Once to the correct dimension and shoes are arced and installed you can check with a brake centering gauge.
You must be careful using the back edge of the cutoff wheel but it can be done for those who don’t have fancier equipment. As always use proper eye protection
I do a lot of brake work and am usually repairing tracks every week.
Larry shepard
Curtis in MA
Senior Member
Because I left the cams in place I can't get a 4 1/5" angle grinder on it. I will try the cut-off wheel.
BRENT in 10-uh-C
Well-known member
This is very true, ...AND if you go by the measurement in Les Andrew's book, it is incorrect when compared to the Ford print. When you use the centering tool to check on the shoes being in the proper location, this becomes very evident.
Curtis in MA
Senior Member
The book says 1". What is correct?
BRENT in 10-uh-C
Well-known member
.
Asking me what the correct measurement is, and using a cut-off wheel to reshape these is sending you down the wrong road IMHO.
The ONLY way to do them correctly if you have welded them is to have a fixture that locates the housing plate in a Mill where the weld can be machined parallel with the mounting bolt holes. The pins riding on those tracks must travel parallel pushing the shoe outward with less than 0.001" deviation out of parallel. Can you hold that kind of tolerance with a grinding wheel? If not, the pin will cause the shoe to push upwards or downward during application which then causes it to be out of centerline with the drum. If the shoes are out of centerline with the drum, you will quickly lose friction in lining to drum contact due to not all parts of the shoe contacting the drum. Ford designed his brakes where the rear brakes carried the higher percentage of braking. Again, I am not trying to be mean or belittle you as many others fall into this same scenario, but times have changed and brakes need to function at 100% to be safe. This is not an area to cut corners or MacGuyver stuff.
Asking me what the correct measurement is, and using a cut-off wheel to reshape these is sending you down the wrong road IMHO.
The ONLY way to do them correctly if you have welded them is to have a fixture that locates the housing plate in a Mill where the weld can be machined parallel with the mounting bolt holes. The pins riding on those tracks must travel parallel pushing the shoe outward with less than 0.001" deviation out of parallel. Can you hold that kind of tolerance with a grinding wheel? If not, the pin will cause the shoe to push upwards or downward during application which then causes it to be out of centerline with the drum. If the shoes are out of centerline with the drum, you will quickly lose friction in lining to drum contact due to not all parts of the shoe contacting the drum. Ford designed his brakes where the rear brakes carried the higher percentage of braking. Again, I am not trying to be mean or belittle you as many others fall into this same scenario, but times have changed and brakes need to function at 100% to be safe. This is not an area to cut corners or MacGuyver stuff.
whirnot
Well-known member
I too used a guage. A 1 inch steel tried square blade works perfectly. For the fronts, I made a guage out of a wood strip. I never removed the tracks. Some say after building these up correctly, a centering guage is not needed, but after reading Brent's comments, I think I will check them.
Curtis in MA
Senior Member
I'll probably get in trouble for this but I'm not a break guy.
If you center or arch the shoes perfectly, then put the drum on and turn the adjustment wedge even one click, don't you change everything?
If you center or arch the shoes perfectly, then put the drum on and turn the adjustment wedge even one click, don't you change everything?
BRENT in 10-uh-C
Well-known member
Curtis, I understand what you are saying however you probably need to take a moment and study how the system works. In theory, you have a 360° round surface of the brake drums. When applied, the brake shoes do not contact all 360° of the drum. For the sake of this discussion, let just assume the rear shoes touch from the 10:00 o'clock over to the 2:00 o'clock position of the drum, ...and from the 4:00 over to the 8:00 position. Theoretically, the centerline of the shoes needs to be at the centerline of the drum at 12:00 & 6:00 position. When the brakes are actuated, the centerline of the shoes (which are at the 6:00 & 12:00 position) push directly towards the drum, and the tracks cause it to go in a straight line towards the drum. Now if the tracks are worn or mis-shaped, it allows the shoe to engage the drum off-center. This allows one end of the shoe to contact the drum with more pressure than the other end, ...which decreases the braking friction. Now to complicate the matter, if the axle housing race is worn, this allows the brake drum to be higher than in the correct centerline of the shoes. Let's just assume that the hub bearing and the housing race is collectively worn just 0.020", that means the bottom shoes engages quicker (by 0.020" of travel) and so more friction happens on the lower shoe and the upper shoe has little to no friction pressure. I trust this is helping you understand why without proper tooling and methods that ensure everything is within proper specs, it is only by luck that you will have quality brakes on a Model-A like they were originally.
For first timers, I would suggest this. If you can find a rear axle housing, set it on the floor small end up. Install a rear backing plate springs and shoes. Operate the adjuster and watch the action. Actuate the wedge and watch the action. See how the track and wedge and springs control vertical movement while being applied. Learn the names as well. There's more than what meets the eye at first glance. The system does work but it is not forgiving.