Mopar Pro wheel Cylinders?

[plymouthcranbrook]

I installed a completely new brake system using Rock Auto parts years ago and have had no problems at all. And my memory such as it is remembers at least some of the items if not all coming in boxes with Kantor labels on them.

[Bingster]

If we wait long enough all of our parts might be made here again.

[Eneto-55]

11 hours ago, Bingster said:

I was wondering when the old cylinders are re-sleeved, what's used for pistons?

 

I take your question to be about the ID after re-sleeving.  I have not had it done myself, but my understanding/expectation is that they ream it out enough that the sleeve's ID is the same as the original specs.

As far as the vendor who said that old cylinders aren't worth rebuilding - that's all we ever did before all of this "replace the entire assembly" approach took hold.  After cleaning them up you can tell if they can be reused.  In my case they were too pitted to be rebuilt by the old methods, and I considered having them reamed out and then plated back to specs with industrial chrome (in the plating shop where I was working at the time), but US made parts were still available then (80-81), and that was cheaper.

[Bingster]

Ivan-b's explanation of the working parts of a cylinder interests me. So the metal diameter of the piston doesn't figure into whether or not to rebuild. It's the rubber cup. My metal piston goes in and out of the bore easily and there is some play. But enough not to use it? 

 

I also see that the rubber cup is conical, so does the wider end of the cup still have enough diameter to fit snugly in a bore that has been made wider from honing? Does that make any sense?

[Curt Lee]

Proof that building a good reputation may take years but ruining one only takes a minute. If you're in business to serve customers, you have to have that mindset; you're SERVING their needs, not being interrupted in your daily routine by them. I sell parts for a living; my customers, aggravating as they CAN be, are still my bread and butter.

As far as the cup size relative to honing; it would take a lot of honing to go oversize enough to make it necessary to go to a larger size cup. The orientation of the cup (flared side in) means that the fluid pushes the sides of the cup outward, the higher the pressure, the tighter the sealing force. Pits in the bore are the enemy.

[Bingster]

I can see how the pressure of the fluid pushes the cup outward to apply the brake shoe, but I'm a little puzzled as to how the tight fit of the cup retracts back into the cylinder after the brake pedal is released. That would mean that the pressure behind the cup would have to be eliminate. No?

Then rubber lip of the cup would have to reverse itself so it could slide back into the cylinder. But the spring is constantly applying pressure toward the front of the cylinder bore. I am missing some important information here.

I don't know if I've described this properly.

 

 

 

 

 

I mean the pressure of the spring would seem to help keep the cup extended. Obvioulsy it doesn't but I don't know why not. 

[desoto1939]

Bingster: I know you have a lot of questions. But trying to get this far indepth will just make it more confussing on your part.  These cars and all cars with brake fluid have all had the same setup since the 1930's.  It is great that you are asking questions but just reassemble them and they will work just fine.

 

Rich Hartung 

[Ivan_B]

18 minutes ago, desoto1939 said:

It is great that you are asking questions but just reassemble them and they will work just fine.

Assuming that the "mirror" is still good, and the cylinder bore is within specs, of course

Also, as it was already mentioned, pretty sure that when a cylinder is sleeved, they bring it back to the original size.

As for the Chinese parts - many-many parts in new cars are made in Asia, this is a big part of how the manufacturers were able to reduce prices (maintain profits). I would personally prefer NOS parts, but this is mostly out of authenticity considerations. Chinese parts can be poor quality, or they can be great quality. You get what you pay for, just look at the parts beforehand. You can usually tell how well it is made based upon the visible appearance of casting, and machining. You can also always measure the new cylinder with a micrometer to make sure it is within specs.

Edited August 3, 2023 by Ivan_B

[soth122003]

Hey Bingster,

The part that part that pushes the fluid and cup back in the cylinder bore, is the big honkin tight spring that is connected to each brake shoe. It has more than enough power to override that small spring in the cylinder. If you have ever changed the brake shoes, you have probably cursed trying to get that spring back into place.

 

Joe Lee

[Ivan_B]

3 minutes ago, soth122003 said:

If you have ever changed the brake shoes, you have probably cursed trying to get that spring back into place.

Good point. By the way, the proper way to do this, is to insert the spring into the shoe, first, and then pull the shoe over to its mounting points using both hands and a foot. Do not attempt to pull the spring into the shoe, already installed, with pliers, etc. This is not safe

[TodFitch]

58 minutes ago, Ivan_B said:

Good point. By the way, the proper way to do this, is to insert the spring into the shoe, first, and then pull the shoe over to its mounting points using both hands and a foot. Do not attempt to pull the spring into the shoe, already installed, with pliers, etc. This is not safe

A proper brake spring tool will work too.

[Plymouthy Adams]

if you do not have the tools, hopefully you will get them....there is no substitute for the proper tool only one that could be your next accident.  

[desoto1939]

The real issue with remanufactured stems from first issue is if the remanufacturer is using a TRUE NOS original manufactured part to obtain the original specifications.

 

So if they can only get a part that is not perfect and or not have the blueprint drawing then they are left with a part that might not be perfect.  Lets take another point here at the sametime.  Some of the parts that were put back into the parts department might be NOS, but they might be there because there might be a small blemish or imperfection on the part.  Some sellers have also stated that even thought a part is LISTED AS NOS it still might not be a perfect part.  So here also lies another issue is used an older original part that might be NOT Perfect.

 

The reproduction manufactures when re-makeing a new part have been know to make the part smaller becauseof trying to get all of the proper measurements and if they are off a little then the parts will not work properly.

 

Yes the Chineese are making new parts for our cars but they have the most current spec's for these new cars and are not trying to duplicate exactly a part that was made over 50-70 years ago and might not have all of the appropriate documentation and design specifications.

 

Also most Automobile manufactures only have to have parts for their cars for around a 10-12 period after the car has stopped being  produced. So even with a modern car you might not even beable to get a part for a car that is still being driven by you.

 

This is just my assessment of remanufacturing parts for cars and truck that are no longer being produced.

 

Rich Hartung

 

[Eneto-55]

34 minutes ago, desoto1939 said:

....

Also most Automobile manufactures only have to have parts for their cars for around a 10-12 period after the car has stopped being  produced. So even with a modern car you might not even beable to get a part for a car that is still being driven by you.

 

This is just my assessment of remanufacturing parts for cars and truck that are no longer being produced.

 

Rich Hartung

 

An example of this: My Dad was a service desk parts salesman (serving the mechanics, not the public) at the Chrysler-Dodge-Plymouth-DeSoto dealership in Tulsa from the mid 50's until some time in the 60's (after which he worked for other makes), and they were tossing lots of NOS parts from the late 40's and into the early 50's by then.  (He actually brought home a brand new transmission for the 53 DeSoto that was the family car at that time.)

[Plymouthy Adams]

at this day and age and given the manner many things may be done in less than a perfect environment, if one is taking a part out of a box that looks old, damage, dirty or mishandled, you are doing yourself and your car a disservice by not taking it down for inspection, clean and reassembly.  Especially in the area of the brakes we cleanliness is everything...where brake fluid is the assembly lube and we all know it has hygroscopic properties.  If this is you, then be it on you.  Could be the difference between an enjoyable outing and the high ride back on the flatbed given you make it back at all.  Not saying this happens but without a bit of an inspection, the likelihood is greater.  

[Young Ed]

2 hours ago, Eneto-55 said:

An example of this: My Dad was a service desk parts salesman (serving the mechanics, not the public) at the Chrysler-Dodge-Plymouth-DeSoto dealership in Tulsa from the mid 50's until some time in the 60's (after which he worked for other makes), and they were tossing lots of NOS parts from the late 40's and into the early 50's by then.  (He actually brought home a brand new transmission for the 53 DeSoto that was the family car at that time.)

Dad was a mechanic at a couple local Ford dealers in mid to late 70s. He told me one day he came out and there was a rolloff full of edsel parts. Brand new horse collar grills sitting in the dumpster etc

[Bryan G]

My first brake job was on a shoebox Ford; I was broke. Cylinders weren't that expensive, but I decided to grab a cheap hone and some rebuild kits. Those cylinders were in terrible shape, with most of them being partially eaten away inside. I did my best...I probably put 20-30k miles on that car over about 10 years. I think I eventually had to replace one cylinder.

 

Rich is right; it's the old "garbage-in/garbage-out" situation. If you don't start by matching a perfect part, what have you got? That Ford? You could buy all sorts of things reproduction, mostly thanks to Dennis Carpenter, but none of it that I bought...none of it...ever matched originals. Most were still quite functional and most folks would never notice the difference, but other items were so far off as to be useless. Weatherstripping has let me down several times, on various models. I recall spending half a day replacing the T-Top gaskets on an early 80s Z28 for a customer. The new ones leaked ten times worse than those old originals!

[Ivan_B]

9 hours ago, Bingster said:

So the metal diameter of the piston doesn't figure into whether or not to rebuild. It's the rubber cup. My metal piston goes in and out of the bore easily and there is some play. But enough not to use it? 

 

I also see that the rubber cup is conical, so does the wider end of the cup still have enough diameter to fit snugly in a bore that has been made wider from honing? Does that make any sense?

As far as I know - yes. If you take a new slave cylinder and remove the rubber seal from the piston - it will slide rather freely inside the bore. It should not be able to go sideways, etc., but it is definitely not a tight fit. I could not find any diagram with specs, for reference, to see how loose it should fit, though.

There are two types of popular seals - the cone and the o-ring, both work in a similar way. The shoes should be very close to the drum for proper operation. The pistons should not be moving much at all. It just applies pressure to the shoe. In fact, when you adjust the brakes, you push the shoes out so that the aforementioned return springs do not push the cylinder too far back. With the self-adjusting cylinders, you have a special sleeve inside the bore, which fits very tightly and moves forward with the piston when you press the pedal hard, but does not allow the piston to go back more than a tiny fraction of an inch.

Do you see any kind of wear or other irregularities on your pistons? If not, I would leave them alone. You do need a new rubber seal and a good "mirror" inside the bore, since this allows the rubber seal to do its work properly.

 

Later: found a slave cylinder specs for a random European car.

Nominal cylinder size - 0.63" (small cylinder).

Gap between cylinder bore and piston: minimum - 0.002" maximum - 0.004"

Edited August 4, 2023 by Ivan_B

[Los_Control]

FWIW, when I work on brakes I always try a panic stop action to see if they hold up.

When I rebuilt the master cylinder in my truck .... It looked like it was worth a shot. The wheel cylinders were toast & I replaced them.

 

So I put it all together & bled the brakes, had a decent pedal & happy. ..... I could drive it like this.  Then I stomped on the pedal just as hard as I could.

The pedal went straight to the floor.     The fluid had leaked around the rubber cup in the master cylinder.

 

I'm only suggesting, you can rebuild your hydraulic brake components .... then test them before driving with them.

Just pulling a fake number out of a hat .... you use your brakes normally you probably have 1500 psi at the wheel cylinders to push the brake shoes.

 

You stomp on the pedal just as hard as you can .... as if a car ran a stop sign you want to avoid a accident  .... you probably have 3000psi going to the brakes.

You would never drive your car normally stomping on the brakes .... But if you can stomp on them several times & they hold up .... probably safe to drive.

 

Same principal when they fill gas welding bottles. ... They hold 2000psi, to test the bottles after the date has run out ... they run them up to 3500psi in a controlled room .... if they survive they get a new 10 year stamp before they need to be tested again.

 

Just thinking, you can throw a kit in them & then test them before you drive on them. And feel confident your brakes are working as they should.

[Rodney_Hamon]

My ‘36 dodge truck was a pain for brakes. My P-23 was easy to find the parts. I used Rockauto and Kanter for most things and then came the rear wheel cylinders for the truck. Couldn’t find them so White Post had to re-re sleeve the rears.  After install they leaked after a time. I sent them back and they checked them and returned to me.  I reinstalled and the same thing.  Then Mopar Pro advertisered ‘36 rears.  Didn’t care what the price was as I just wanted the brake leaks misery to stop. They worked !  I’m happy.  Btw, I got real good with that drum puller. Ha

[Bingster]

I guess this is one of the problems with hydraulic brakes.