Poor braking with Morrow prewar hub

[srfndoc]

I just rebuilt a prewar Morrow hub (dated F4) and although it works ok, the braking power is less than desired (requires way too much force to get it to brake). What parts/procedures should I be looking at to remedy this. Here is the hub when I first broke it down:







I replaced all three bearings as they were pretty worn but the rest of the parts looked good so I thru it back together. Does anything stand out here?

 

[Andrew Gorman]

No coaster brake works very well at all. In city traffic, get used to dropping you feet and skidding on shoe leather.

 

[Freqman1]

Two things I would look at are brake shoes and cone adjustment. Seems to me the Morrow is a little more sensitive to cone adjustment than a ND. V/r Shawn

 

[Balloonoob]

I have one of these I need to rebuild as well. Are the 8 pieces in the top picture all there is to it? I think that the grooves on the brake sleeve (in the very bottom left) are worn down to smooth. I have heard that you can basically saw new grooves sometimes but I'm guessing it might be easier and less headaches to replace it. Good luck. Out of curiosity (since I am having this problem) are you noticing unusual play between braking and the gear catching to drive forward? Perhaps my issue is cone adjustment related.

 

[Gordon]

According to the book, a worn brake cylinder is usually the culprit of poor braking. Whenever I rebuild a coaster brake hub I remove any glaze in the hub shell by using a brake cylinder hone in my drill. It often makes a huge difference. If you don't have a hone, simply using emery paper or fine sandpaper by hand will work.

 

[fattyre]

Ha @Gordon ! Just typed the same thing!

Check that your braking surfaces aren’t burnished. Especially the hub shell. Wire wheel or steel wool the hub shell real well. And make sure those shoes shine!

Overall I get good consistent braking performance from Morrow hubs, but some of mine do have a bit less power than others. I suspect the shoes are worn therefore diminishing power.

 

[fattyre]

@Balloonoob

If parts 113 & 114 have chipped teeth, that can cause engagement problems. I’ve also seen when part #110 has broken in two and this leads to a funny feeling between braking and pedaling.

 

[srfndoc]

Thanks everyone for the feedback. I did check the cone adjustment and it was still within limits but the outer bound (1/32"). There were no worn teeth and the two parts engaged normally. I did use some wet/dry 800 grit sandpaper to rough up the braking surface/hub surface but that didn't seem to help much.

How do you tell if you have a worn brake sleeve? I know the later hubs have ribs in the braking surface and some even cut them in to simulate the later brake sleeves (As Balloonoob mentioned). Anyone know where to get a new brake sleeve? Here's a pic of the internals when I pulled it out so you can get a good look at the sleeve:






Thanks

 

[bikecrazy]

When I first started rebuilding coaster brake hubs, I used bearing grease throughout. Not happy with the braking, I did some research. The solution for me was to use bearing grease on the bearings, and motor oil on the braking surfaces. The result was much better braking performance.

 

[srfndoc]

When I first started rebuilding coaster brake hubs, I used bearing grease throughout. Not happy with the braking, I did some research. The solution for me was to use bearing grease on the bearings, and motor oil on the braking surfaces. The result was much better braking performance.

Same here... only bearings get grease and the rest get a 30Wt. oil. I've done many ND hubs this way and always get good stopping power with minimal pressure needed. That's the issue here... its stops but requires way too much pressure.