"41 VS '42 front wheel cylinders

TomC750

TomC750

Senior Member
I have realized when shopping for brake parts that starting with 1942 there are differences from the '39 - '41 cars. I then read somewhere front wheel cylinders have a larger bore in the later cars. Are there other differences?

Specifically, I would like to use the later ones if the backing plates are the same.

TomE
 
Backing plates should be DIFFERENT. The difference is in the bottom retainer. The 41 and earlier have the round hole in the brake shoes , the 42 and later have the round with parallel flats . The 41 earlier have external adjustment on the bottom where as the 42 later eliminated that and use a fixed but moveable bottom.
 
39-42 use the same backing plate, P/N 91A-2013 on the front. All using the 01A prefix brake shoes with the round holes at the bottom which are adjustable. Changed to 51A-2013 in 1946 which eliminated the bottom adjustment as Ggmac states. Third Gen and Carpenter show the front wheel cylinders as a 21A -2061/2 part numbers and fitting 39-48 so the answer appears they will fit on the front.
 
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Tom, while the backing plates may be different, the part where the wheel cylinder is fitted is the same, so you can use the later cylinder in an earlier backing plate. The later cylinders are more commonly available and are often used in earlier cars.

Mart.
 
From Bob Drakes site:
Each is an exact copy of the original 1942-48 style and comes completely assembled and ready to install. Because of the larger piston size, they work perfectly for 1939-41 when used in pairs. Replace both cylinders at the same time.
Ggmac, you were close. I'll have to say my 42 has given me an education several times.
 
I answered my own question early this morning by taking apart one of my old front cylinders. Sure enough, the bore in the old one is1 1/4 as opposed to the new one 1 3/8. Made sense that the suppliers only sell the later version.

Now, moving on, I still do not have a satisfactory pedal. I have vacuum bled extensively, adjusted several times, the last time after driving up and down the driveway using the brakes as much as possible. This helped a bit. I am no stranger to adjusting these Lockheed brakes, my 1930 White has the same system. Today I will try to adjust the master cyl rod. Looks like fun. I am so anxious to take my prize on a real ride, it feels like a new car in the short ride in the driveway.

I really appreciate all the responses, it is very reassuring to receive them.

TomE
 
Today I adjusted the Master cyl rod. I was afraid it would be stuck with rust, but both the locknut (not tight against the Adjustment nut) and adjustment nut were free. So I adjusted an arbitrary amount, Viola! Good pedal. So I took it up and down the drive again and messed up the gravel stopping numerous times!

Thought I was done, but a hard look at connections revealed a slight weep at the left rear line to cyl connection. Trying to tighten it further was no help. So I removed the whole line, took my flaring tool and pressed down fairly hard on the flare. Reinstalled, no leak.
As an aside, I would have been done with this job over two weeks ago, but a brake shoe delivery via USPS was hung up at a terminal for 6 days, then it took a detour to Tallahassee Fla. Originally it was only a 350 mile trip to our home in Tenn. Pony Express would have been quicker.
Our grandson sold an item to another party, both item and tracking# disappeared. Customer paid and is not happy. Refund paid to customer. In both cases the holiday was approaching, but my shipment left on the 11th. We have terrible local mail service, often delivered to wrong box.

My next job is to put interior back together.

TomE
 
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