Surge brake help

[Lake time]

I have a double axle trailer with a 12000lb rated surge brake master cylinder just put all new baking system on free backing the issue I ran in to was the drums where dragging and popped my bearing buddies of going down the road the grease was boiling now mind you I had the shoes adjust all the way out and was still dragging on all tires could that 12000 lb cap surgery brake be to much for a 8000lb boat

 

[gm280]

Lake Time, don't actually mean you had all the shoes adjusted all the way in? I mean the least amount of adjusting is the further away from the drums. So if you actually adjusted them all the way out, that IS the reason they are dragging. And IF the grease was boiling like you stated, you will need new shoes AND probable new bearings and seals now as well. JMHO!

 

[Lake time]

No they where backed out not in it was going to adjust them in but since I have them backed out idk what to do next I can't back them off any more

 

[alldodge]

Can you spin the wheel by hand with the axle jacked up and tire off the ground?

 

[Lake time]

Yes it spins about 2 revolution per tire do to barrings preload

 

[alldodge]

Spinning freely means brakes are no dragging, so I don't collate how your getting heat. Only way to get heat is with some form of friction. Do you hear any growling or rumbles when the wheels are spun?

Doesn't matter if you have a cylinder greater then the trailer weight, only if it's less. Surge brakes work off of momentum applied to the brake coupler, as it increases the trailer slows down, when it slows down pressure is reduced.

 

[Lake time]

No noise coming from them I'm a diesel mechanic I know a bit of hydraulic braking systems but this surge brake **** is new to me lol yeah what it's doing is not making any sense to me lol its almost like it's over braking I took a drum off one axle everything looks OK but it seems to be more of a problem on the rear axle

 

[bruceb58]

The larger capacity surge brake unit had nothing to do with the problem. Surge brakes are self regulating so only enough brake pressure is applied to keep an equilibrium when stopping.

 

[bruceb58]

Trailer level?

You using equalizing hitch?

 

[alldodge]

No noise coming from them I'm a diesel mechanic I know a bit of hydraulic braking systems but this surge brake **** is new to me lol yeah what it's doing is not making any sense to me lol its almost like it's over braking I took a drum off one axle everything looks OK but it seems to be more of a problem on the rear axle

Does the rear axle drag any?

 

[Scott Danforth]

When you replaced the break actuator, did you replace the wheel cylinders? My last trailer, the wheel cylinders developed enough corrosion in the wheel cylinders that they would hang up when extended.

The surge brake system is nothing more than a master cylinder mounted to a sliding member dampened with a shock, actuating either drum brakes or disc brakes.

Causes of hanging brakes would be:
Using in conjunction with some WD hitches
Improper hitch height
Damaged actuator
Damaged slave cylinders

 

[Fleetwin]

No noise coming from them I'm a diesel mechanic I know a bit of hydraulic braking systems but this surge brake **** is new to me lol yeah what it's doing is not making any sense to me lol its almost like it's over braking I took a drum off one axle everything looks OK but it seems to be more of a problem on the rear axle

Surge brakes are no different from any other hydraulic braking system. Except the actuator takes the place of a foot pedal. Same principles apply.

If they are dragging:

1. The actuator is not releasing.
2. The wheel cylinders are not releasing. That could be corrosion in the wheel cylinders or you have mechanical binding in the hardware.
3. Improper hitch height. Trailer must be level.
4. Emergency stop lever (on actuator) is partially deployed.

 

[gm280]

Obviously there is something going on to boil the wheel bearing grease. So until you find the culprit tread lightly. Because whatever is causing such heat will break sooner then later. And if the grease was actually boiling, something I've never seen before myself, then the wheel bearing seals and even the rubber wheel cylinder cups and dust caps have to be melted and shot. JMHO!

 

[thumpar]

I went from a 5000lb actuator to a 7500lb actuator on my trailer. That is not your problem. I would think that if it was the brakes causing the heat you would have a hard time pulling the trailer and maybe even a tire lock up. Is the trailer you have meant for a boat that size and weight?

 

[keith2k455]

My first guess is bearings to tight. If you jack the wheel up and spin as hard as you can, it should spin way more than two revolutions. Either bearings are to tight or you need to back the shoes away from the drum (I would refer to this as in, like in towards the spindle. )

Either way, it sounds like the bearings are probably scorched. I'd make sure to inspect them.

 

[dingbat]

May be two different things.
Rear brakes on a tandem always work harder because of how the equalizer works. Reason why single brake systems on tandems go on rear axle.

Pull you bearing buddies and make sure the cotter pins are installed/bent properly. For whatever reason, an improperly installed will walk a bearing buddy housing out of the hub in short time. Can't explain, but seen it many times.

Bearing should have 0.005 to 0.010" of end play. Should have a very slight play when pushing/pulling on tire.

 

[bruceb58]

Rear brakes on a tandem always work harder because of how the equalizer works. Reason why single brake systems on tandems go on rear axle.

When you have brakes on 2 axles, both axle's brakes work equally since the brake fluid pressure is identical.

 

[smokeonthewater]

Yep... Neither "works harder" on tandem leaf spring trailers the front is more likely to lock up, hop, skid due to the design of the equalizer but otherwise they are the same.

 

[Lake time]

Everything is brand new Dico 2478100 Model 10 Zinc Plated Hydraulic Drum Brake Actuator and Titan Free-Backing Hydraulic Trailer Brake Assembly pluses bearings from tsc

 

[dingbat]

When you have brakes on 2 axles, both axle's brakes work equally since the brake fluid pressure is identical.

what you say is true but your ignoring the other half of the equation, contact pressure between the tire and the road.

The contact pressure on the rear axle will always be higher than the front because of the inverse axle loading of the equalizer design in braking situations.

The problem comeswhen braking pressure exceeds contact pressure and the front wheel skids or hops. At that point, the braking efficiency for that axle is in the dumpster and the rear has to take up the entire load.