Front Drum brake befuddlement (1 Viewer)

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Dec 29, 2005
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Craig, CO
As long as the cups inside the cylinders are not nicked or tore you should be able to free them up and keep going. The OEM boots usually survive great, but the cups inside can get destroyed if you have heavy rust and debris in there.

I had some ramps the wrong way on mine for who knows how long, got them all right a couple years ago and that helped alot. I also had the brake pedal adjusted incorrectly, fixed that and that helped alot too. Regular adjustment of the brakes is key too.

What bothered me a great deal a couple years ago was the condition of my cylinders. My fronts were acting up, so I got in there with the plan to replace the drums as I knew they were at their wear limits 20 some years ago, and put on new shoes. What I found was a mess. I had done a trip a year or so before where we had to cross a pretty deep bog/marsh. The interior of the brakes were covered in the residue of this crossing. I don't usually do deep mud. I then found at least a couple of cylinders stuck. Upon opening them up I found far more rust and water issues than I expected. These were brand new OEM cylinders in 1996, so I didn't think they had degraded to that level.

The front drum cylinders changed about 4 times in the US market, and I was unable to find rebuild kits for mine on a April of 73. (Cruiser Outfitters probably had them, I was on a time crunch.) I ended up getting like one kit finally from OReilly's. I cleaned everything up, honed the cylinders and swapped around all the best cups and made it work. I put a generous amount of SilGlyde silicone grease inside the boot and the cylinder/piston area above the cups and on all the adjusters. I know that may be taboo, but so far I have not had any issues, and I hope it will displace the moisture that gets in between the walls and seizes up the outside piston/rod that actually pushes on the shoe. The liberal antiseize they had been covered with in the past on the adjusters seems to just get hard. I have been using the SilGlyde alot for this stuff over the antiseize, another decade will tell me if that worked or not.

I have used this SilGlyde trick on disc brake pistons and other drum brake cylinders, so far no leaks in the past few years. As I said I was really surprised by the water intrusion in them. Some was probably water in the brake fluid over time, but the vertical nature of the cylinders does not help, and I don't think all the rust came from the one wheeling trip, probably 20 some years of daily driving was to blame too. Amazingly the rear cylinders on my 1996 T100 with 260,000 miles at the time were almost spotless inside. I had only flushed the brake system once since I had it in the last decade. I cleaned all parts and put them back together with their original cups, they are fine. Also rebuilt the front calibers on my FZJ80 with 170,000 miles, they were spotless inside too, thought maybe they were sticky cause we had a brake vibration, but found no evidence, and that truck had not had any good flushing's of the brake fluid either. So again, I was pretty surprised to find the cylinders so degraded on fairly new parts and good maintenance and minimal abuse. I think they are just prone to water intrusion by design.
 

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