'40 Ford Wheel Cylinders

[mike42]

Morning ....

I want to rebuild all the wheel cylinders this Summer (if it ever stops snowing in Northern Michigan) and I'm looking online for rebuild kits. C & G is where I normally buy everything due to their good service, etc.

It notes 2 rebuild kits for a '40....one is 1" x 1.25" and the other is 1" x 1.38". How do I know which one to buy ? Wait and tear everything down and go from there ?

Thx....Mike

[Kurt in NJ]

The original cylinders were replaced with the later style in many cases, you will have to measure or buy both style kits

[19Fordy]

DRAKE says his 40 front wheel cylinders have 1 3/8 x 1 bore.
Rear have 1 1/8 x 1 wheel cyl. bore.
Here's some good reading about bore size.

https://www.jalopyjournal.com/forum/...bigger.782368/
and
https://www.fordbarn.com/forum/showt...linder+quality


There was also a discussion last year about poor quality of foreign made wheel cylinders as some have the bleeder hole screw incorrectly located and machined. Read about it here.
https://www.fordbarn.com/forum/showt...linder+quality

Measure the old ones on your car first before buying anything. If your present wheel cylinders are original you might want to just stay with them.

[deuce_roadster]

I just had the 2 rear cylinders (1 x 1 1/8) for my 40 coupe sleeved with stainless steel for less then $100. If nobody near you does that, look up Hagen's auto parts in Puyallup WA online. While I do have new cylinders, for reasons stated above, I sleeved my originals. Many use the later cylinders with lager bore.

[mike42]

Guys.....these have to be the original wheel cylinders, as the car only has 85,000 original miles. The car was made in May of 1940. I'm assuming they would have a FoMoCo stamp on them which I'll check when weather gets better.

Many thx....Mike

[Ken/Alabama]

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Originally Posted by mike42

Guys.....these have to be the original wheel cylinders, as the car only has 85,000 original miles. The car was made in May of 1940. I'm assuming they would have a FoMoCo stamp on them which I'll check when weather gets better.

Many thx....Mike

I doubt very seriously if they will be stamped with the later FoMoCo. More likely Lockheed.

[19Fordy]

Mike, Unless your wheel cylinders are badly rusted and pitted,I bet you will be able to hone them and rebuild them without problems. You might want to rebuild the master cylinder also to keep it all in top shape.

[Flathead Fever]

If they are "Ford" script wheel cylinders you definitely want to try and save them on an original car. I'm not sure if there were Ford script wheel cylinders? If there were you can bet that the majority of Ford script wheel cylinders got tossed in the trash unless they were The chances of the originals surviving without being pitted badly after 80-year's is slim.
Just because the car only has 80K miles on it has nothing to do with if the wheel cylinders will still be original. They do not wear out from mileage. They get rust pits from moisture getting in there. They can go bad just sitting in the garage if the fluid is not changed. It just depends on how much moisture was absorbed into the fluid and how often the fluid was changed.

There is no reason to ever sleeve a brake cylinder unless they are pitted so bad your trying to save the casting. The fluid should be flushed periodically anyway regardless of if they have been sleeved with stainless or not. If you change the fluid you will never get pits and you will never need to sleeve them.

Rock Auto has Raybestos wheel cylinder kits for 1940s Fords but they are not real clear on the bore size. Most local auto parts stores can get hydraulic brake parts for Early Fords, you don't not need to order them from a vintage Ford store. That way you save on shipping which has gotten stupid expensive.

If the wheel cylinders are pitted in the middle of the cylinder it doesn't matter because the pistons and seals do not make contact at that spot. Do not try and hone any pits out of the center of the cylinder you will enlarge the bore too much and they will leak. The only pits that matter are where the pistons and seals ride. Just use a ball hone with some brake fluid or WD-40 to lightly hone them. Clean them real good afterward with soap and water just like you would the cylinder in an engine. Lube the bore with brake fluid or brake cylinder assembly lube made by McKay and reassemble. The brake fluid is fine if your going to assemble the cylinders and use them right away. The assembly lube works great too but its better for parts that will be assembled and then sit around for awhile. Just make sure to get the cups installed facing the correct direction. Its self explanatory if you look at the cups. One direction, the fluid will press against the lips of the cups and make a seal against the bore. Installed backwards, the fluid will push the lips away from the bore and they will leak.

Replace all the brake springs on old cars. They will break if you do not. They are only good for five to ten year's before they snap. Do not stretch them into place with anything that will leave a mark on them or they can break at that spot. Stretch them by the hook ends with brake spring pliers. The springs are cheap, get rid of the old ones so a year from now you don't have to go back in there again to repair a broken brake spring.

Make sure somebody has not installed the shoes backwards. I've seen it several times on Early Fords. Most everybody that works on their own cars has been taught that the long shoe goes to the rear and the short shoe goes to the front. That is only on "self energizing drum" brakes. The long shoe always goes towards the front on a Early Ford.

Measure your wheel cylinders before ordering kits. Somebody could have upgraded to the larger wheel cylinders.

Wheel cylinder size. If you do not care about originality I would use the larger bore Early Ford cylinders which would give you slightly better braking. The best way to explain this is the pressure from the master cylinder is pushing against the piston in the wheel cylinder. Lets say its 200 lbs. of pressure. Now lets pretend that pressure is actually three 200 lb. men pushing against the wheel cylinder piston. If we increase the size of the piston so there is room for a fourth 200 lb. man to push against the piston your going to have a greater force being applied. Even though there is still only 200 lbs of pressure against the entire piston's surface its being applied against a larger area. If three 200 lb. guy's are pushing a car and a fourth jumps in to help push together they can push a heavier car or push the same weight car with less force having to be applied. You might as well use the larger wheel cylinders and get that little extra pushing power applied to the brake shoes unless you need to keep the wheel cylinders original.

So why don't they make the wheel cylinders even bigger? Their size is limited to the size of the piston in the master cylinder. That piston has to be able to move enough fluid to push four wheel cylinders and still have an extra amount reserve movement so the pedal stops at about halfway of its travel. If the wheel cylinders size were increased the pedal would need to move further towards the floor to move more fluid. If you increased the master cylinder's piston size to move more fluid you would have to push a lot harder on the brake pedal. The smaller the master cylinder piston the easier the pedal pressure. You just have a little wiggle room with the piston sizes for everything to work right.

[Flathead Fever]

I went out in the garage to my brake shelf and dug out some backing plates. Not one of these has a Ford or FoMoCo script on the wheel cylinder. Three of them do have Lockheed USA on them.

[mobileparts]

If you want to go BRAND NEW -- I have the Master Cylinder, Wheel Cylinders, Brake Hoses, & Brake Shoes -- with "package deals" available....

Always best to simply call me -- Craig -- 516 - 485 - 1935... New York... you

[mobileparts]

If you would like to go Brand New -- I have the Master Cylinder, Wheel Cylinders, Brake Hoses, & Brake Shoes -- and "package deals" available...

Always best to simply call me -- 516 - 485 - 1935... Craig ... New York...

[mike42]

Guys..... thx for all the info. I really appreciate it !

I'm going to check Rock Auto and buy parts for Spring rework. We got snow again last night, so Spring is a ways off.

Thx...Mike