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TR2/3/3A TR3 Type "A" front brake caliper rebuilding
- Thread starter JFeher
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TR3driver
Great Pumpkin - R.I.P
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Re: TR3 Type "A" front brake caliper rebuilding
I've done it, but it was a long time ago. Wasn't too bad at all, and I didn't even have to replace the pistons. The biggest hassle is usually getting the old pistons out.
However, I've heard that some of the replacement dust seals don't fit properly.
I've done it, but it was a long time ago. Wasn't too bad at all, and I didn't even have to replace the pistons. The biggest hassle is usually getting the old pistons out.
However, I've heard that some of the replacement dust seals don't fit properly.
Re: TR3 Type "A" front brake caliper rebuilding
John,
I have 3A calipers on my TR2. Did a rebuild on them with Moss parts and had no real problems then or since. Used a compressor to get the pistons out easily and the seals were a bit "fiddley" but do-able.
I'd say go for it. Way cheaper. Save your money for the really necessary expensive stuff. (not that good brakes are not necessary, they just do not need to be expensive)
John,
I have 3A calipers on my TR2. Did a rebuild on them with Moss parts and had no real problems then or since. Used a compressor to get the pistons out easily and the seals were a bit "fiddley" but do-able.
I'd say go for it. Way cheaper. Save your money for the really necessary expensive stuff. (not that good brakes are not necessary, they just do not need to be expensive)
Geo Hahn
Yoda
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Re: TR3 Type "A" front brake caliper rebuilding
I last redid mine about 3 years ago -- I did not split them (saw no need) and the boots I got at that time fit fine (though they can be a little tricky to install). I did replace the pistons as they were not looking so good.
If the calipers are still on the car and the hydraulics working I like to use that system to push the pistons out. I remove the pads and use an assortment of thin strips of wood (e.g. masonite) and C-clamps to keep the pistons from coming all the way out. Usually one will move first, after it has gone aways I block it and force the other one to move. Rinse, repeat -- stopping before either is all the way out so you can do the same process on the other side. Once they have come out most of the way they can be easily removed using air or (if you do not plan to re-use the pistons) channel-locks.
If you are not using DOT-5 and have ever considered it, this might be a moment to think about it.
I last redid mine about 3 years ago -- I did not split them (saw no need) and the boots I got at that time fit fine (though they can be a little tricky to install). I did replace the pistons as they were not looking so good.
If the calipers are still on the car and the hydraulics working I like to use that system to push the pistons out. I remove the pads and use an assortment of thin strips of wood (e.g. masonite) and C-clamps to keep the pistons from coming all the way out. Usually one will move first, after it has gone aways I block it and force the other one to move. Rinse, repeat -- stopping before either is all the way out so you can do the same process on the other side. Once they have come out most of the way they can be easily removed using air or (if you do not plan to re-use the pistons) channel-locks.
If you are not using DOT-5 and have ever considered it, this might be a moment to think about it.
hondo402000
Darth Vader
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Re: TR3 Type "A" front brake caliper rebuilding
I did mine a few years ago, just make sure you clean the groove out really well with a small rotary wire wheel, the first rebuild the seals started leaking because of rust in the groove. I also put SS pistons in mine, so far the second rebuild is working great
Hondo
I did mine a few years ago, just make sure you clean the groove out really well with a small rotary wire wheel, the first rebuild the seals started leaking because of rust in the groove. I also put SS pistons in mine, so far the second rebuild is working great
Hondo
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JFeher
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Re: TR3 Type "A" front brake caliper rebuilding
Thanks guys. I'm going to try rebuilding them. It's about a $400 difference even with new pistons. I've just started putting the suspension back together and I'm finally getting to the brake system. I'm going to pick up a rubber tipped air gun and see if that will pop the pistons out. The car had been sitting for over 25 years and all the hoses and lines were rotted away. I'm hopping the internals aren't rotten. These don't split open they seem to be one piece. Since everthing will be new maybe I'll try the DOT-5. Isn't that 100% silicone?
Thanks guys. I'm going to try rebuilding them. It's about a $400 difference even with new pistons. I've just started putting the suspension back together and I'm finally getting to the brake system. I'm going to pick up a rubber tipped air gun and see if that will pop the pistons out. The car had been sitting for over 25 years and all the hoses and lines were rotted away. I'm hopping the internals aren't rotten. These don't split open they seem to be one piece. Since everthing will be new maybe I'll try the DOT-5. Isn't that 100% silicone?
TR3driver
Great Pumpkin - R.I.P
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Re: TR3 Type "A" front brake caliper rebuilding
Pretty much, though it does have some other additives, like dye (the purple color) and "seal sweller". I'm a big fan, seems like all of the hydraulic components last much longer with DOT 5. I credit it for the fact I've not needed to rebuild calipers since 1990 or so (moved the wrecked 3A calipers to the TR3, because its original calipers had the bleed screws frozen).
When using air to remove the pistons, IMO it's a good idea to insert a strip of wood or similar between the pistons while applying the air. It helps cushion the impact when they do pop loose.
JFeher said:
Pretty much, though it does have some other additives, like dye (the purple color) and "seal sweller". I'm a big fan, seems like all of the hydraulic components last much longer with DOT 5. I credit it for the fact I've not needed to rebuild calipers since 1990 or so (moved the wrecked 3A calipers to the TR3, because its original calipers had the bleed screws frozen).
When using air to remove the pistons, IMO it's a good idea to insert a strip of wood or similar between the pistons while applying the air. It helps cushion the impact when they do pop loose.
hondo402000
Darth Vader
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Re: TR3 Type "A" front brake caliper rebuilding
they should come apart, it would be difficult to maching the piston bores with a one piece unit, I will be very surprised if the pistons come out, if the pistons are rusted as most are about 1/2 way back, they will probably get stuck, keep us posted
Hondo
they should come apart, it would be difficult to maching the piston bores with a one piece unit, I will be very surprised if the pistons come out, if the pistons are rusted as most are about 1/2 way back, they will probably get stuck, keep us posted
Hondo
Re: TR3 Type "A" front brake caliper rebuilding
I have been told, and it also says the same in the How to Restore... book, that you can make a fitting from a bolt and grease zerk and use a grease gun to push the pistons out of the calipers if they won't come out with air pressure. I understand it takes a lot of brake cleaner to get all the grease out but still better than buying new calipers. Also, the How to Restore... book says to use methylated spirits to clean brake calipers. That is Denatured Alcohol in the US. Lowes sells it by the gallon and not very expensive, probably cheaper than brake cleaner.
Regards,
Bob
I have been told, and it also says the same in the How to Restore... book, that you can make a fitting from a bolt and grease zerk and use a grease gun to push the pistons out of the calipers if they won't come out with air pressure. I understand it takes a lot of brake cleaner to get all the grease out but still better than buying new calipers. Also, the How to Restore... book says to use methylated spirits to clean brake calipers. That is Denatured Alcohol in the US. Lowes sells it by the gallon and not very expensive, probably cheaper than brake cleaner.
Regards,
Bob
TR3driver
Great Pumpkin - R.I.P
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Re: TR3 Type "A" front brake caliper rebuilding
Right, although it's only one big screw plug, not two. To remove it, you're going to need one of those things that looks like a cross between a house jack and a hydraulic press. I don't even know the correct name, but there's a photo in one of my antique machining books at home. Here's a smaller version (shown being used to remove the pole pieces in the generator). The one for the brake calipers has a frame on both sides, and a big forcing screw to hold the blade into the slot.
Right, although it's only one big screw plug, not two. To remove it, you're going to need one of those things that looks like a cross between a house jack and a hydraulic press. I don't even know the correct name, but there's a photo in one of my antique machining books at home. Here's a smaller version (shown being used to remove the pole pieces in the generator). The one for the brake calipers has a frame on both sides, and a big forcing screw to hold the blade into the slot.
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Re: TR3 Type "A" front brake caliper rebuilding
I did mine a couple years ago, with new pistons. Several sources warn against taking the halves apart, and it is not necessary. Nor is it necessary to remove the big plug. Cleaning the grooves for the seal and the boot is essential. I used dental picks and wire wheels on a Dremel. Get some rubber lube and it will go right together.
Bob
I did mine a couple years ago, with new pistons. Several sources warn against taking the halves apart, and it is not necessary. Nor is it necessary to remove the big plug. Cleaning the grooves for the seal and the boot is essential. I used dental picks and wire wheels on a Dremel. Get some rubber lube and it will go right together.
Bob
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JFeher
Senior Member
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Re: TR3 Type "A" front brake caliper rebuilding
I used compressed air and 3 out of 4 popped right out. The 4th one I had to work back and forth until it came out. Not as bad as I thought it would be. They seem to be in good shape. There was some minor rust "stains" inside the
cylinders. I polished that off with some 00 steel wool and denatured alcohol. The grooves for the dust covers have some rust but I think I'll be able to clean that up. I think they are in good enough condition to rebuild.
I used compressed air and 3 out of 4 popped right out. The 4th one I had to work back and forth until it came out. Not as bad as I thought it would be. They seem to be in good shape. There was some minor rust "stains" inside the
cylinders. I polished that off with some 00 steel wool and denatured alcohol. The grooves for the dust covers have some rust but I think I'll be able to clean that up. I think they are in good enough condition to rebuild.
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martx-5
Yoda
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Re: TR3 Type "A" front brake caliper rebuilding
The original TR3 calipers are one piece units. They have a big threaded plug on one side to facilitate the machining.
Also, as mentioned above, make sure you get both grooves in each bore very clean of all dirt and rust, or assembly will be difficult and seals may get cut when the piston is pushed in. I've found that running a dental type pick or scribe around the grooves works very good for loosening up the dirt and rust, followed by some wire brush work. Alternately, if you have access to a glass beader, that would be ideal.
Edit: I see you posted while I was still looking for a picture of the A style calipers.
Yes, the the insides of those bores and grooves look very good. Definitely a candidate for rebuilding. Don't worry about any "staining" or pits in the bores, as the seal seals on the outside of the pistons and in the seal groove.
hondo402000 said:
The original TR3 calipers are one piece units. They have a big threaded plug on one side to facilitate the machining.
Also, as mentioned above, make sure you get both grooves in each bore very clean of all dirt and rust, or assembly will be difficult and seals may get cut when the piston is pushed in. I've found that running a dental type pick or scribe around the grooves works very good for loosening up the dirt and rust, followed by some wire brush work. Alternately, if you have access to a glass beader, that would be ideal.
Edit: I see you posted while I was still looking for a picture of the A style calipers.
Yes, the the insides of those bores and grooves look very good. Definitely a candidate for rebuilding. Don't worry about any "staining" or pits in the bores, as the seal seals on the outside of the pistons and in the seal groove.
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JFeher
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Re: TR3 Type "A" front brake caliper rebuilding
Those outer grooves are going to be a PITA. The inner ones cleaned up well with the alcohol/steel wool and a small screw driver. The outer grooves are more of a challenge, a lot more rust. I can see how a dental pick would work well. Since they don't split it's hard to access the area with any kind of power tool.
Those outer grooves are going to be a PITA. The inner ones cleaned up well with the alcohol/steel wool and a small screw driver. The outer grooves are more of a challenge, a lot more rust. I can see how a dental pick would work well. Since they don't split it's hard to access the area with any kind of power tool.
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Re: TR3 Type "A" front brake caliper rebuilding
Since your crossover tubes are so clean, I suspect that you handled them a bit. When you put the wheels back on, get behind them and check to see that the crossovers are clear of the wheels. As TR3 Driver said in a recent post, the wear on the tubes from wheel contact is noiseless and swift.
Bob
Since your crossover tubes are so clean, I suspect that you handled them a bit. When you put the wheels back on, get behind them and check to see that the crossovers are clear of the wheels. As TR3 Driver said in a recent post, the wear on the tubes from wheel contact is noiseless and swift.
Bob
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JFeher
Senior Member
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Re: TR3 Type "A" front brake caliper rebuilding
I replaced the crossover tubes along with the seals and pistons. I don't have rotors and wheel bearings to mount the hubs/wheels yet but I'll keep that in mind. Thanks for the tip about using the dental pick. It loosened up a lot of stuff in the seal groove I couldn't directly see. I used DOT-5 when I assembled the calipers and like you said, It went right together.
I replaced the crossover tubes along with the seals and pistons. I don't have rotors and wheel bearings to mount the hubs/wheels yet but I'll keep that in mind. Thanks for the tip about using the dental pick. It loosened up a lot of stuff in the seal groove I couldn't directly see. I used DOT-5 when I assembled the calipers and like you said, It went right together.