Morgan +4 Forum

Posted this on the Vintage 3 Wheeler Forum, but also posting it here to get more eyes on it.

Recently purchased a '38 Super Sports. It's been off the road since the early '80s so I'm going through it mechanically to get it back to road worthy. First on the list is to get the parts on order to rebuild the brakes. The car was converted to hydraulics fairly early in life I think. Believe the brake cylinders and MGTC, but have no idea on the master cylinder. I think it should be British given the heritage of the rest of the car. I don't recognize it as anything pictured on the Moss Motors site. It's a single circuit, has an unusual 3 bolt mounting flange and 1.250 inch bore. Any help on it's origin would be greatly appreciated.

It is not from a TC, or a TD for sure.
Something you might consider is going out to Wilwood and replacing it with a new compact universal MC of the same or similar bore size. When I restored my TC some years ago I found that the MC had been replaced with a then leaky TD unit. Repro TC master cylinders were quite pricey at the time and since it lived under the floor and was not visible, I replaced it with a new Wilwood unit of proper size.

This one -https://morrisregisterspares.co.uk/product/bm003-1936-1939-morris-104-124-brake-master-cylinder/

If you look at the spec sheet it's marked 830

Thank you Phil, I believe you are correct. I was looking at the Morris 14 HP which looks very close, but seeing the "830" designation in the parts designation is a further indication this is most likely correct. Thank you very much for this lead!

Thanks Stephen, I may go that route eventually. I would like to try the existing cylinder if I can rebuild it. I haven't cleaned and inspected the bore yet, but judging how it came apart, I'm thinking it's useable. The wheel cylinders certainly are. I'm really wondering if I need an 1 1/4 bore to run just a couple of wheel cylinders. Seems line a 3/4 bore would push enough fluid and the smaller bore would give greater wheel cylinder force for better braking.

My car has an actuator plumbed into the system presumably to run the rear brake as well. The actuator has a clevis on it, not hooked to anything now, but I imagine it had a cable running to the rear brake at some point. That contraption may have taken a fair amount of fluid to run.

Greetings..Anothe option would be to have the cylinder sleeved in stainless. That assumes the setup worked correctly to begin with.

Tim

If the master cylinder is standard Girling/Lockheed pattern, checking the Wilwood catalog is a pretty good idea.
If originality is to be maintained, White Post Restorations will sleeve it back to original size and fit the proper seals and O rings so that it will function properly.

Of course, the Wilwood solution is the least expensive. You can get adapters for the more modern master cylinder .

If you want the originality to be kept, and have a plug and play installation, White Post is the way to go. There are other master cylinder/slave cylinder restorers as well, but White Post has been around for a very long time. They have a good rep and evidently are reasonably priced. With the stainless sleeving of your old master cylinder, it will likely never need replacing or honing ever again.

Appreciate the input on White Post. After looking a little further,the master is pitted to the point where a hone won't get it. I can buy new wheel cylinders from Moss. Will look at Wilwood for a replacement master. The 3 wheelers were all mechanical brakes originally so not worried about originality.

FWIW...I just last week used a Wilwood .75 in master cylinder to replace the Girling in my Morgan 4/4 (1968; single M/C) and it works well. I recommend you bench bleed it before installation, though. Same threads as the Girling it replaced. Got it through Amazon.

White Post sleeves the master cylinder, so the pits are not a factor. The stainless steel sleeve will last forever. This will preserve your current master cylinder.

Of course, the Wilwood or other Girling pattern master cylinder will be less expensive.

One thing that you can do with the Wilwood master cylinder is to allow a remote mounted reservoir. This may make checking and replenishment of the reservoir much easier.

I may have the existing master sleeved. Looking at the travel of the piston, I may just need the larger piston area.
Thanks all!

The master will be sleeved to original specs. There will be no change in bore or travel.

If you need a larger master cylinder, you will get a shorter pedal travel, and more pedal pressure (higher effort) to work the brakes. That would require a new, larger master cylinder to start with.

If you are happy with the current brake pedal travel and pressure, sleeving your old master cylinder will give you the original brake feel and pedal travel. No surprises.

Understood. I don't have any experience with the braking system as I purchased the car as a non running project. 3 wheelers are notorious for poor braking so thinking a smaller diameter MC for greater pressure would be a move in the right direction. Looking at the mechanical linkage however, I will stick with the large one for the initial build.

A smaller master cylinder will soften the brake pedal feel somewhat, increase the travel while increasing the pressure to the brakes. A softer pedal with more authority (less pedal pressure effort). This can be something that you might want, or not... If the brake response is to your liking now, leave it alone (the original bore size).

I do twin master cylinder installations from time to time, and often have to change the master cylinder sizes to get the feel and pedal travel that I like. There is nothing wrong with doing this. But, if you like the way that the brakes work now, stick with what you have as far as bore size. If you decide to change the master cylinder, keep the same bore for the new one so that it feels like the old one.

Just a personal comment relative to White Post Restorations. The company is very professional, perform excellent, excellent work and back up their work with lifetime guarantees. Granted, it has probably been 25 years since I had them sleeve and restore all the components of my E-Type brake system but they did a great job and were timely in the turn-around. I used to talk with them at the Charlotte Autofair when I went there years ago.

lep

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Laurence Plott
1962 Morgan Plus 4
1966 Jaguar E-Type
1960 MGA