Hydraulic drum brake Master Cylinder

[Lake Pirate]

I have a 1991 dual axle trailer with hydraulic drum brakes. I towed the trailer home and the brakes worked ok, but I want to rebuild them. The actuator is marked, "Dico no 10, 17550". My problem is that the master cylinder cap is frozen in place and I can't get it off. I've soaked it in WD-40, penatrating oil, and tried prying the edges, nothing moves it. The master cylinder looks like cast iron and the cap is plastic. I'm afraid the PO might have used Lock Tight or something on it. Any ideas will be appreciated.

Thanks,

 

[tpenfield]

Re: Hydraulic drum brake Master Cylinder

Have you used a BFW? (Big Wrench)

I recall that the cap on my actuator does not want to come off unless I over power it.

 

[Lake Pirate]

Re: Hydraulic drum brake Master Cylinder

Yeah, I've tried as large a wrench as I can fit in the space. The trouble is that the center section of the cap starts to twist and distorts the cap like its hollow. I actually starts to collapase under the strain.

 

[bruceb58]

Re: Hydraulic drum brake Master Cylinder

Fortunately, you can buy a new cap.

http://www.championtrailers.com/dico_brake_coupler_parts.htm

As well as a new master cylinder it it ends up also having a problem.

 

[Lake Pirate]

Re: Hydraulic drum brake Master Cylinder

I had kind of figured I'd end up destroying it getting it off and having to replace it. Just hoped someone might have a trick to getting it loose. I'm off to order parts.

Thanks for the input.

 

[lncoop]

Re: Hydraulic drum brake Master Cylinder

Yeah, I had the same experience with my model sixty. When they get like that you pretty well just have to destroy them to get them off. While you're ordering you might as well grab a couple, and I can promise you you'll need a new master and wheel cylinders, so do yourself a favor and order those as well. You'll be glad you did. Good luck and welcome aboard.

 

[dingbat]

Re: Hydraulic drum brake Master Cylinder

Get a big hammer the beat the coupler off the tongue and buy a new one. You can buy a new coupler for less than the cost of the parts to rebuild the old. If you count your time into the equation, it becomes a no brainer.

 

[bruceb58]

Re: Hydraulic drum brake Master Cylinder

Get a big hammer the beat the coupler off the tongue and buy a new one. You can buy a new coupler for less than the cost of the parts to rebuild the old. If you count your time into the equation, it becomes a no brainer.

Model 10 Dico which OP has is $280 fron Champion Trailer. New master cylinder is $85. Am I missing something here? Nothing else really wears out on these couplers so not sure why he would want to buy a complete new one.

 

[Lake Pirate]

Re: Hydraulic drum brake Master Cylinder

Thanks for the welcome Incoop,

Wheel cylinders are already on my work list, but the master cylinder plunger still works smoothly and rebounds quickly, do you recommend replacing it as a precaution?

For the price of parts, I think I'll make some repairs rather than replacing everything. I have lots more time than money. lol

Thanks

 

[lncoop]

Re: Hydraulic drum brake Master Cylinder

Thanks for the welcome Incoop,

Wheel cylinders are already on my work list, but the master cylinder plunger still works smoothly and rebounds quickly, do you recommend replacing it as a precaution?

No, if the MC is functioning properly I wouldn't replace it. I'm just pleasantly surprised to hear that it is. Maybe it had fluid in it unlike mine. Might want to take a peek at the shock in the coupler at some point.

 

[Lake Pirate]

Re: Hydraulic drum brake Master Cylinder

Bruceb58, thanks for the link to Champion. I'll take a longer look tonight and get the parts to fix it up.

Incoop, this is how I tested it, let me know if I need to do somethinhg else. Using a board and the safety chains as shown in the owners manual, I pressed in the coupler and watched for a return. Got approx .5 to .75 inch movement, slow return which I expected from the shocks. Then I removed the breakaway lever and manually worked the master cylinder plunger with a pry bar. It moved freely. Then I slightly loosened the brake line at the M/C and watched for an oil drip as I moved the plunger. There was oil. But not sure how much. I could hear the brakes pads moving. My plan is to start with the M/C and work toward the brakes replacing whatever I need to.

Thanks,

 

[lncoop]

Re: Hydraulic drum brake Master Cylinder

That's a solid plan, Pirate. Before you order anything online check the yellowpages for a trailer parts store in your hood. You might get lucky.