Brake Wheel Cylinder Sizes

Jock(OR) · May 18, 2022

I have an old (1973) 850 Case bulldozer. The "wheel" cylinders for the brakes push levers that mechanically clamp the twin brake discs. The "wheel" cylinder is a single bore with a flat bottom held in place with two 1/4" bolts. A double-ended rod engages the piston in the cylinder and an adjusting bolt on the lever.

This design is used on many Case models of tractors, backhoes, and crawlers.

My problem is that my cylinders (part number A 50557) were originally 1-1/8" bore, and all the replacement cylinders have 7/8" bore. One of my cylinders was junk, and I replaced it with a new unit. That side takes twice the pedal effort to turn the dozer!

I cannot find any information on bore size of Case slave cylinders. Everyone gives the mounting dimensions and rod length, but not bore.

My remaining cylinder has "BENDIX 2226169" cast into it. I cannot find anything using this number, but a couple of listings cross to early Case 580E cylinders part numbers A62483 and A168473. Does anyone know what the bore size is on these cylinders?

wore out · May 18, 2022

Have you checked into having the "bad" cylinders "sleeved" as is commonly done on irreplaceable antique car brakes?

A 'net search will get you started, "sleeving antique brake cylinders".

On another tangent, are the castings of the new, undersized bore cylinders you have the same O.D. as the original castings, if so they could be bored to 1.125".

Hemmings Motor News typically carrys lots of ads for outfits that are able to rescue brake cylinders, as well.

thehickdaddy · May 18, 2022

does that image look correct?

everything i have found so far with that bendix number lists a 7/8 inch bore.

also as a side note, the casting numbers on wheel cylinders and master cylinders are casting numbers and therefore can be any one of 3 bore sizes or more.
i have run into that problem many times over the years. when working with older machines, having your original and correct part rebuilt can be the best option.
i have sent out terrible looking master and wheel cylinders out to be sleeved and they always come back and work great for many more years.
just my thoughts
Untitled URL Link

John Saeli · May 18, 2022

We can furnish the 1-1/8 Cyl. you need for a fraction of the CASE price. 315-585-9826

Jock(OR) · May 18, 2022

Unfortunately, all those parts are long gone. The piston was trash, too, and I can't find a part number for a 1-1/8" piston, either.

Jock(OR) · May 18, 2022

Yes, it looks like that. I took a photo of the numbers cast into the remaining old cylinder, and the numbers I listed are correct. The bore measures 1-1/8" and that agrees with the note I wrote 30 years ago when I rebuilt the brakes.

jean claude marleau · May 18, 2022

Your old Case part number has been sub to a newer part number G109413 and if you google this number there is plenty for sale like
on amazon for 36.00 and broken tractor has them for sale for 35.00

RGMartin · May 19, 2022

Make sure to get ones rated for the type of fluid you are using. Some systems use brake fluid, some are mineral oil/Hytran; the seals are not compatible. Some sellers don't know, or are deliberately vague in their descriptions. Same goes for the master cylinders. It really is a pain when you get a system totally repaired only to have it fail in a short amount of time. It may not be huge issue on a crawler, but on a machine that will see road use in a hilly traffic filled area it is a big deal.

Jock(OR) · May 19, 2022

The bore diameter of the G109413 is 7/8", which is the problem that I am complaining about. The original part had a bore diameter of 1-1/8".

Just because a manufacturer gives a superseded part number doesn't meant that it is an exact replacement. It seems that companies no longer care about their customers, only convenience for themselves and making more money.

Jock(OR) · May 19, 2022

I'm using DOT 5 silicone brake fluid, because of the original master cylinders being designed for DOT 3 brake fluid. It is pretty inert, which is why I changed over to it. Since I changed, I have had no corrosion in the brake system. It is not supposed to damage Nitrile O-rings, which is what the mineral oil cylinders use.

The remaining original slave cylinder I rebuilt 30 years ago with a Nitrile O-ring still doesn't leak.

John Saeli · May 19, 2022

850 Dozer Parts Manual is clear, OEM Slave was & is Mineral Oil, not DOT 3. The CASE OEM Slave from a Dealer is 1-1/8 Bore, Mineral Oil.
Everything else on the net is Knock Off. The Slave we offer is 1-1/8 Mineral Oil, a duplicate of the OEM for a fraction of the CASE price.
Those are the facts.

Brokengun · May 19, 2022

Sounds like John Saeli has the answer.

Jock(OR) · May 19, 2022

My 850 Owners Manual calls for DOT 3 brake fluid. It was printed at the time the dozer was made. Current parts manuals were created almost 50 years after the dozer was made.

Case parts manuals say that the 7/8" bore slave cylinder is the proper one. That is wrong. If they say to use mineral oil with the original master cylinders, that is wrong, too.

I assume that Case believes that everyone has converted to their replacement parts, and changed to mineral oil. I believe that they don't care if the parts work properly. "If the customer doesn't like how it works, they can buy a new machine."

Using the original master cylinders, the original 1-1/8" slave cylinders apply 1.65 times the master cylinder force. The replacement 7/8" cylinders apply 1.00 times the master cylinder force. The operator must push much harder to apply the same amount of braking force. The original design has reasonable pedal pressure. The replacement design requires way too much pedal pressure.

The strange thing is that no one seems to want the customer to know what the most important working dimension, the cylinder bore, is.

Brake Wheel Cylinder Sizes

Jock(OR)

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wore out

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thehickdaddy

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John Saeli

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Jock(OR)

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jean claude marleau

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RGMartin

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