Drum to disk conversion -- installation #2

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Feb 24, 2006
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Solomons Island, MD
Now that the old drum parts are off and the spindle is bare, it is now time to install the disk kit.


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Now all that remains is to install the brake line and bleed the lines.

Tomorrow the other hub gets converted, and sometime later this week or on the weekend, I'll connect the brake lines and bleed them.

Installing the brake lines and bleeding the lines will be another how-to post with pics. :D :D :D
Awesome, thanks for the great and very detailed pics, Porkchunker!

My trailer is in desperate need of the same upgrade, but I've been reluctant to dig into it without knowing what lies ahead, whether I'll have the right tools, etc.

-- Tom
Forgot one thing. When converting from drum to disk, a small checkvalve in the master cylinder (contained in the surge hitch) must be pierced to relieve pressure when the cylinder is not compressed. Drums need about 5 lbs of minimal pressure when relaxed (not sure why), but disks must have absolutely no pressure on them when relaxed. If you don't pierce the checkvalve, the constant pressure causes the pads to drag on the disk and overheat the pads, disk, and bearings/seals. Before I post the pics for bleeding the lines, I'll post some pics here on how to disassemble the master cylinder and make the mod.
Excellent post! :D

Even better than most "Official" Auto shop manuals I have used.

Thanks for adding more superb documentation to ClassicParker.

This type of "how-to" content is the best way to keep this site and our on-line community alive and thriving. :mrgreen:

Porkchunker":d6m4azlh said:
Forgot one thing. When converting from drum to disk, a small checkvalve in the master cylinder (contained in the surge hitch) must be pierced to relieve pressure when the cylinder is not compressed.


Is this what you are trying to do?

http://www.championtrailers.com/remove_ ... _valve.htm

I've been researching this project for my trailer..

-- Tom

Have received conflicting guidance from several folks over on TheHullTruth about this modification.

Your link is the first "official" guidance I've seen.

Although the instructions clearly indicate not to "pierce" the valve, that seems to be what most folks do, rather than removing the master cylinder from the actuator, disassembling it, removing the valve, reassembling it, and inserting it back in the actuator. I need to pull the actuator apart to clean and grease all of the rollers, so I may go ahead and do it right, rather than the piercing shortcut.


If its any help, all you have to do do is unbolt the master cylinder from the actuator (4 bolts) and the whole thing slides right out. I just removed mine to take a look at it and was amazed that it was so easy.

I discovered that I need to completely re-do my brakes, but the actuator was welded to the trailer frame. This might limit my choices for an upgrade, but I still have to do some research to see what my options are.

Are you installing a reverse lockout solenoid?

-- Tom
Yes, I'll be installing the reverse lockout solenoid.

If when I remove the tubing adaptor, I can see the checkvalve, I may pierce it with an awl (as most people do), rather than disassemble the actuator and master cylinder.

Will keep all posted as to my final decision and any pics showing the process.
Ok...I was in a hurry to finish the task so I could support Wish-A-Fish on Saturday, 26 Aug. So, I took the shortcut and pierced the checkvalve rather than disassembling the actuator and master cylinder.

Took the brake line off the rear of the actuator unit. Removed the tubing adaptor (part #23 in the Titan/Dico 10 actuator diagram), and tried to pierce with a long sharpened nail. No go...the checkvalve kept moving away from me riding in the bore of the master cylinder under spring pressure. So...I chucked a 1/16" drill bit in my handy-dandy DeWalt battery operated drill and drilled it out. Very soft metal, and went very fast. I flushed the master cylinder body with fresh brake fluid (pumping the break-away lever) to ensure no drillings were in the body, that might gum up the works. Reassembled, and bleed the brakes.

This particular actuator gets bleed by pulling back on the break-away lever (directions are in the Titan/Dico 10 pdf you can download from their site).

It was getting dark, and I didn't get pictures of either operation. :( :( :(

First test ride was from home to Sandy Point State Park near Annapolis, MD. Took about 35 minutes to get there at 55-60 mph. Tested the brakes several times (come up to speed, apply the brakes to replicate a quick stop), and they were obviously working...I didn't get that "pushy feeling" I had with the inop drum brakes. When I got to SPSP, I checked the temp of the hubs. They were much hotter than the idler hubs on the other axle, but not too hot to put my hand on and hold there. Since I had done my high speed stops on the side road approaching the park, I figured the heat was from the braking.

Went fishing and supported WAF.

On the way back home, I was careful to not apply the brakes to the trailer (did my best to coast to a slow roll through lights and intersections). Checked the hub temp about 1/3 of the way home on a wide siding on the Interstate. Hubs were still hotter than the idlers, but as before I was able to keep my hand on them. Figured that maybe the bearings were too tight. I've done wheel bearings a thousand times, and figured I didn't screw this up.

When I got home, I backed the trailer into my drive (up hill). Durn brakes caused my testosterone loaded Power Stroke to die...twice. The more coal I poured to that diesel the more those brakes worked against me...so obviouly those disks are working. Never had that with the drums. Even new, the drums couldn't match my PSD in reverse at idle. Not those Kodiak disks. So...one of the mods I'm going to have to add is a reverse lock-out solenoid.

Finally got her in place, but not after attracking the attention of the neighbors. Good friend wandered over and claimed it sounded like a tractor pulling contest over here. :shock: :shock: :shock:

Next day, I cleaned up the boat, and then turned my attention to the new hubs. Pulled a wheel to expose the hub and disk rotor/caliper assy. There was a slight dragging of pads on the disk rotor. Was able to push the pad on the wheel cylinder side back away from the rotor...so there was no residual pressure in the lines (piercing the checkvave worked). Wiggled the hub/rotor assy, and could feel a slight movement, which meant the bearings were not too tight (e.g., not preloaded).

So...it looks like I'll have to disassemble and clean/grease the actuator. It doesn't move to the rear and back to the relaxed position easy...sometimes I have to pop the clutch on the truck a bit to get it to pull out to the relaxed position. That is not the correct operation...it should slide forward simply by pulling the trailer forward with the truck. The actuator is not easily moving to the relaxed position, and therefore is probably giving me some residual pressure in the brake lines while in normal tow. The manual says they should give 5 years of service with "proper maintenance." Well...I haven't done squat to this actuator in the 4 years I've had it.

Will keep you posted on my actuator disassembly, cleaning, greasing, and reassembly (with pics of course). The disassembly will give me another chance to capture pics of bleeding the brake lines. I'll re-stage the pics of piercing the checkvalve while I'm at it. Since I'll be disassembling the acutator, I'll disassemble the master cylinder and remove the checkvalve (which is the manufacturer's recommendation anyway). So maybe I can attone for my my sin of not getting the pics last Friday. :) :) :)
This link indicates that hot hubs are normal with disk brakes. Mine are hot to the touch, but I can keep my hand on them without getting burned. Better check what kind of grease I'm using though and ensure it is the type suitable for disk brakes.

Extract from the link:


Disc brakes normally run hotter that drum brakes due to partial contact of pad and rotor during normal highway travel; whereas drum brakes have a return spring that retracts the brake shoes with virtually no contact between the shoes and drum.

Your disc brakes during normal highway travel should be "very warm", but still allow you to put your hands on the hub without burning. However during frequent braking periods, such as stop and go braking, they may be to hot to touch.


Also be sure that the master cylinder tubing adapter orifice is bored to a minimum of .0625" . This will facilitate the return flow of fluid to the master cylinder on the return stroke.


Since disc brakes run hot, it is important to use a high Temperature grease specifically intended for disc brakes. Other greases may lose their viscosity at higher temperatures and liquefy, allowing them to sling out past the seal or dust cap. CHECK FOR WORN SEALS. In most installations it will be necessary to install SPINDLE-LUBE dust caps and bellows plugs, to allow the grease to expand during high temperature operation.

Link to the full article: http://www.championtrailers.com/DISC_BR ... RTICLE.HTM
Well I got back from my business trip to LA, and it is drizzling.

Was going to tear down the acutator, clean, grease, and reassemble. But with the drizzle, I decided to oil and grease without a teardown. Was able to get an oil can down onto the internal rollers, and grease the big roller on top. Actuator moves fairly easy now. Will haul her to Solomons later today and will report back about the heat issue.
Thank for the documentation I'm going through the same thing on the trailer that used to be under my Grady as one of the pre-for sale upgrades. This info has been very useful.

I just removed those four bolts that hold the master cylinder in...and it started raining again before I could get it out. AARGH.... :?
Looks like I'll be placing another order for parts. Master cylinder was bone dry and completely frozen. :(



Guess I won't have to worry about puncturing any valves after all. I'll just order a disc brake master cylinder. :)
If the rest of the parts are in similar shape, you might want to purchase an entire actuator, rather than just the 1 or 2 parts you need. I found that the prices of the individual parts quickly became more expensive than a complete set. If I remember correctly, just the master cylinder is ~$65, while the whole actuator was $110.

-- Tom