Technical Model A/Hydraulic Brake Conversion Question(s)

In my mind I've been building the '31 Model A Tudor I recently bought in preparation of the actual build. I have a question about brake conversion.

I'll be switching the '31 axle for a '33-'36 axle to get a bit of drop and have '37''-'41 round back spindles as well as the parts to convert to cross steering. I have the backing plates, some of the backing plate hardware and a pair of useable front hubs/drums to convert to hydraulic brakes. I'm curious if the later spindles and hydraulic brake drums will space the front wheels to a wider track width? I'm hoping it doesn't or at least not by much. The A is currently sporting 17" wire wheels which I intend to keep and hope they stay tucked neatly under the fenders as they are now.

Another option would be to keep the drag link steering and adapt the hydraulic brakes to the Model A spindles, but don't know what effect that might have on the front wheel track width.

Just when I think I know something about hot rods I realize I don't know nearly enough!

Lynn

 

The spindles and drums will not affect the track width, the axle will, however. I could be mistaken but I think the kingpin bores are closer to each other on that axle so you will lose some width, but not much.

 

Thanks. I haven't double checked with a tape measure, but per Nostalgia Sid's website the Model A and the 33-36 axle are the same kingpin to kingpin.

I might be able to do some measuring on my Model A today and then do a mock-up of the later hydraulic brake drum with the '37-'41 spindles and see if there is a difference kingpin to wheel mounting surface distance. I guess I'm a bit lazy to have not measured in the first place, but figured as common as the hydraulic brake conversion is that the answer would be on the tip of the tongue of many who have done it.

Thanks for your reply. I'll get busy measuring.

Lynn

 

After some measuring it appears the hydraulic brakes would put the center of the tire about 3/4-in farther out on each side. That's assuming that the outer edge of the wire rim center would seat on the hydraulic brake drum at the base of the tapered area on the drum and I'd have to use the spacers that are sold so that the wheel tightens down properly.

Lynn