1" master cylinder rebuild kit alternative

[67Dart273]

Drum vs disc may not matter as far as the cups. May not matter for the pistons either. The big thing about drum vs disc is where are the ports in the cylinder bore and length of the pistons, unless you are keeping the originals, and "do the cups fit?" Also, of course is the residual valves

Decades ago, when REAL catalogs had interchanges and such, we sold Wells for awhile, then Raybestos, but we filled in with Wagner and whatever else we could get when we needed odd stuff. We had a HUGE Wagner catalog about foot thick, and one thing that was in there was a big casting number reference. you could look up (such as) a master, and it would give you the bore, ALL the parts individually, including listing all the parts (individually) that were in a kit. We did not stock those pieces per se, but sometimes robbed kits and then re-ordered the pieces to make them back up

I don't remember ever seeing such a catalog section from Raybestos. When I first got into parts, Raybestos catalogs were a PITA. You had separate books for shoes, for hardware, and for hydraulics. So you had to look an application up about 6 times to get everything.

In this day and age of computers, there is NO excuse why parts suppliers cannot do better.

 

[Mecki]

Here's some pictures I just took of the pistons and seals from a 1970 Valiant with original power disk drum brakes and a 1970 Duster with original manual 10" drums. The disk/drum master is #2225541 and the drum/drum master is #2660808. The seals ID measures are actually the OD dimensions of the pistons so the seals should be slightly smaller. Both are 1" bore.

 

[Mecki]

Haven't tried yet.

I have a feeling if you find a rebuilt 1" master these days it has been board out to 1 1/32"

Rock Auto has many new 1" cylinders for Mustangs. Not rebuilt so the 1" bore could be true. I was looking at DYNAMIC FRICTION 35554014 and some other for about $40. I'm tempted to order one but before its here its $100++.

 

[scatpackbee]

Great info. Thanks!

 

[Dana67Dart]

Rock Auto has many new 1" cylinders for Mustangs.

my only concern there is a new MC might have different length and dia pistons and the bore might be drilled for its ports in a different location. My original thinking was a 1" disk drum Bendix manufactured Mustang MC MIGHT have the same internals as a 1" disk drum Bendix manufactured Dart MC, key word is MIGHT.

 

[Mecki]

my only concern there is a new MC might have different length and dia pistons and the bore might be drilled for its ports in a different location. My original thinking was a 1" disk drum Bendix manufactured Mustang MC MIGHT have the same internals as a 1" disk drum Bendix manufactured Dart MC, key word is MIGHT.

I understand your thinking. That was my thoughts also since those new cylinders are reproductions made by other manufacturers they are not necessarily exact copies of the originals.

There are many car brands that had 1" tandem master cylinders in the 80's, 90's and 2000. Mercedes W163 1999-2005, BMW 5-series 1995-2004, Land Rover Discovery 1989-1998, Toyota Hi-Lux II 1988-2002, Toyota Camry 1986-1996, VW LT-40 1975-1996, ... Saab, Volvo, Audi, Nissan, ... and many other from that era

I have seen in the pictures of many repair kits with the seals only that they are pretty similar to what I'm looking for. Since the OD 1" is known it would only be necessary to find seals with close enough ID and thickness.

If I just could find a dealer who would bother to do some measuring.

 

[Mecki]

So I'm thinking of taking a different approach to this. There are several 1" repair kits with the seals only for $10-$15.
I found 20-25 kits that are promising. Here's a couple of examples:

So why not make pistons for the seals instead of looking for seals with the right dimensions? The 1" OD is what matters. For the price of these I could buy several kits that appear to be close to what I need and perhaps even some seals will fit directly on the old pistons.

Scan the old pistons to CAD and make necessary changes to the OD and width of the seal groves. The CNC machine will make a piston for the new seals. I could even use only one seal size to keep it simple.

To manufacture a piston from a aluminum rod in a CNC machine is pretty simple, much easier than making or finding a NBR seal of a specific dimension.

My daughters husband operates a CNC machine in a small metal company. They make relatively small sets of parts to the big industry. It could be possible to have it done there. He's also a Mopar man and has a 1969 Dodge Monaco.

 

[Mecki]

I ordered 6 different kits for $70. Lets see how this works out.

 

[Dana67Dart]

Scan the old pistons to CAD and make necessary changes to the OD and width of the seal groves

Measuring would be MUCH more accurate. As you pointed out not a very sophisticated part.



BUT.... LIABILITY upon failure, Brakes are the single most important part of a car (steering second) if it fails and someone dies (or worse doesn't but is incapacitated the rest of their life) and the failure can be traced back to the piston... I don't want to be on the receiving end of that court case. (Yes I was brought up in California, and it shows)

 

[CRUZE 418]

This is the MC that's on my '69 Dart. Front disc, rear drum. O'Reilly, 1.03 bore.

 

[Dana67Dart]

This is the MC that's on my '69 Dart. Front disc, rear drum. O'Reilly, 1.03 bore.

My bet is you can not tell the difference from a 1" especially when not being able to test side by side or scientifically. About 6% more leg force needed, 100 lbs of leg force would need 106 lbs with the larger master.

 

[CRUZE 418]

I don't have power brakes on any of my cars, I don't feel that it takes a lot of pedal pressure for stopping. OMG, the power brake and power steering gods are going to eat my lunch!

 

[Mecki]

This is the MC that's on my '69 Dart. Front disc, rear drum. O'Reilly, 1.03 bore.

Wow, that's good info. A part number helps alot. The RAYBESTOS MC36412 part search took me to RockAuto and they have it listed for 71-76 Dart/Valiant and 76-77 Aspen with manual disk brakes. Bore 1 1/32". (They have also CENTRIC 13063019 DYNAMIC FRICTION 35540016)
Then there is also RAYBESTOS MC36406 listed for 73-75 Dart/Valiant power disk brakes,. Bore 15/16". According to the FSM the Kelsey-Hayes calipers were no longer an option. The power booster was a Midland-Ross Single Diaphragm

I found out that according to the FSMs the Kelsey-Hayes fixed caliper brakes came with a 1" master cylinder up to 1970. From 1971 and on the bore was 1 1/32". I don't know if there was a manual option, both systems I have are power with Midland-Ross Tandem Diaphragm. (70 Valiant and 71 Dart).

Since both 1" and 1 1/32" cylinders were used with Tandem Diaphragm power boosters in K-H disk systems, I would prefer using a smaller bore master cylinder in a manual system. If I just removed the power booster and kept everything else unchanged the 73-75 15/16" bore cylinder could be a good choice.

 

[Mecki]

Measuring would be MUCH more accurate. As you pointed out not a very sophisticated part.



BUT.... LIABILITY upon failure, Brakes are the single most important part of a car (steering second) if it fails and someone dies (or worse doesn't but is incapacitated the rest of their life) and the failure can be traced back to the piston... I don't want to be on the receiving end of that court case. (Yes I was brought up in California, and it shows)

Scan to get the shape drawing instead of starting from scratch and check and correct all dimensions. I have already measured the original pistons.

About liability...hmm...that's not the first concern I have in mind when I try to repair something. If the part is properly planned and manufactured I'm satisfied. I'm certainly not going to ask some authority if I'm allowed to do something. If I would the answer would most probably be "NO" because there's no one who wants to take any responsibility. As long as manufacturing or repairing some part isn't clearly prohibited I'll assume it's allowed. Asking unnecessary questions just leads to more and more prohibitions and that again kills the initiative and ingenuity.

 

[Dana67Dart]

I don't have power brakes on any of my cars, I don't feel that it takes a lot of pedal pressure for stopping. OMG, the power brake and power steering gods are going to eat my lunch!

I took PS OFF of a 67 Dart convert. Not needed and "The parts you don't add, don't cause you no trouble!"

Both of my 67 Dart Converts are NO power brake and NO PS. (one was ordered that way by my dad and the other I'm making that way)

 

[Dana67Dart]

About liability...hmm...that's not the first concern I have in mind when I try to repair something. If the part is properly planned and manufactured I'm satisfied. I'm certainly not going to ask some authority if I'm allowed to do something. If I would the answer would most probably be "NO" because there's no one who wants to take any responsibility. As long as manufacturing or repairing some part isn't clearly prohibited I'll assume it's allowed. Asking unnecessary questions just leads to more and more prohibitions and that again kills the initiative and ingenuity.

I was never implying that anyone ASK for permission to make or repair a part, I'm an ask for forgiveness kind of guy, but product liability its just something that is in the back of my mind ALL the time

 

[Mecki]

I was never implying that anyone ASK for permission to make or repair a part, I'm an ask for forgiveness kind of guy, but product liability its just something that is in the back of my mind ALL the time

We probably have the same opinion on this. I would never accept a part or repair that I have made if I wouldn't honestly believe or know that it's as good/strong or better than the original, especially if it could be a safety issue.

 

[Dana67Dart]

We probably have the same opinion on this. I would never accept a part or repair that I have made if I wouldn't honestly believe or know that it's as good/strong or better than the original, especially if it could be a safety issue

In my earlier years... I made a pitmal arm out of 2 other arms. I had a professionally welded, but I got nervous so I had it X-ray checked. Absolutely 0 penetration in the middle, infact there was a gap and it looked like Swiss cheese where it was welded. I went in a different direction.

 

[Mecki]

In my earlier years... I made a pitmal arm out of 2 other arms. I had a professionally welded, but I got nervous so I had it X-ray checked. Absolutely 0 penetration in the middle, infact there was a gap and it looked like Swiss cheese where it was welded. I went in a different direction.

I was actually thinking of welding and X-ray when I wrote my reply. Over here welding on steering parts and control arms is strictly prohibited fort obvious reasons. Not everyone would be so thorough and really ensure the quality of the repair as you are.

 

[Mecki]

I got the kits that I ordered and made some measuring. Most of the kits had seals with IDs about 15-16mm and various heights that can be used to repair a drum/drum master cylinder but the ID is too much for disk/drum pistons. One kit had seals that fit the disk/drum pistons. (The first picture of the 3 pictures of kits I posted earlier.)

Original seals ID measured from the OD of the piston. ----------->This is a kit for WV LT 75-96. (Frenkit 125044) 3 seals on pistons.

The smaller ID seals were not included in any kit. I'm thinking of making 2 press fit sleeves (11,1mm x 15,1mm x 4,9mm) out of alumina and use the same size seals in all 5 positions. With this kit I would be missing 1 seal. The sleeve could be made for a seal with any ID.

Then there is the residual valve. There is 2 1" kits that I didn't order:

These are for a TOYOTA Hiace Van 87-06. These are the only kits with residual valves I found.

There are still some 1" kits with seals that appear to have a smaller ID than the kits I have. I will probably buy more kits to sort this out.

 

[Reed1970]

Everyone thinks the MK-474 is obsolete, still out there from Dorman for 1"..

Dorman Products - TM59051

Do you know if the seals on this kit would work for a front disc kit? Also a 1” bore

 

[Reed1970]

I got the kits that I ordered and made some measuring. Most of the kits had seals with IDs about 15-16mm and various heights that can be used to repair a drum/drum master cylinder but the ID is too much for disk/drum pistons. One kit had seals that fit the disk/drum pistons. (The first picture of the 3 pictures of kits I posted earlier.)

View attachment 1716381030 View attachment 1716381017
Original seals ID measured from the OD of the piston. ----------->This is a kit for WV LT 75-96. (Frenkit 125044) 3 seals on pistons.

The smaller ID seals were not included in any kit. I'm thinking of making 2 press fit sleeves (11,1mm x 15,1mm x 4,9mm) out of alumina and use the same size seals in all 5 positions. With this kit I would be missing 1 seal. The sleeve could be made for a seal with any ID.

Then there is the residual valve. There is 2 1" kits that I didn't order:

View attachment 1716381022 View attachment 1716381023
These are for a TOYOTA Hiace Van 87-06. These are the only kits with residual valves I found.

There are still some 1" kits with seals that appear to have a smaller ID than the kits I have. I will probably buy more kits to sort this out.

Do you happen to have any part numbers for the 1” disc/drum kits? My pistons and springs are great. Just need new seals

 

[Dana67Dart]

Do you know if the seals on this kit would work for a front disc kit? Also a 1” bore

I'm 99% certain the pistons and seals in the drum drum master are different than the disk drum.

Look at photos of the two.

 

[Dana67Dart]

? My pistons and springs are great. Just need new seals

Check Ford mustang etc of the same era.

Many are also bendix and 1 inch

 

[dadsbee]

Do you know if the seals on this kit would work for a front disc kit? Also a 1” bore

No idea, but what do you have to lose if all you need is seals and your master is leaking. Can't see them making the seals for 1" bore in different sizes. Buy a kit and see what you get..