wet hubs boiling

[bucky7680]

My buddy just got a new boat that came with a trailer that has dual axels with disk brakes on the front axle. The hubs are the wet type, which use 50wt oil instead of grease and have clear plastic caps to check the oil level. When we got the boat ramp (10 min drive) and we were preping the boat to launch the oil started to boil on the front axel and the clear plastic caps cracked causing the oil to leak. (oil and lake no good) He had replacement caps which we replaced along with new oil. We thought that the brakes were sticking so we put in the lock out pin for the drive back. When we got back to his house it did the same thing. He has launched his boat several times before with out a problem. My question is are the brakes sticking or are they out of adjustment? Can disk brakes be adjusted like drum brakes?

 

[Reel Poor]

Re: wet hubs boiling

If it's just one wheel, jack that wheel up and give it a spin, if the brakes are holding it will be noticeable. Also listen fo a groweling noise, possibly bad bearings.

 

[Silvertip]

Re: wet hubs boiling

Bad bearing or spindle nut too tight would be my guess as well.

 

[bucky7680]

Re: wet hubs boiling

Both front hubs are doing it. We'll jack up a wheel, give it a spin and see what happens. If the brakes are draging can disk brakes be adjusted like drums?
Thans for the input.

 

[Silvertip]

Re: wet hubs boiling

Disc brake pads normally remain in light contact with the rotors and are not adjustable. It may be that the master cylinder is sticky and not releasing fully which certainly could cause a great deal of heat. Before you jack up the wheel, make sure you pull ahead a short way to ensure the brakes are not engaged. If the wheel turns hard, either the bearings are tight or the brakes are indeed dragging.

 

[Reel Poor]

Re: wet hubs boiling

If the brakes are draging, and you know the coupler is pulled out as far as it will extend, losen the brake line at the master cylinder, if this frees the brakes the master cylinder may be incorrectly installed.

 

[bucky7680]

Re: wet hubs boiling

Reel Poor we'll try that out also.We need to solve this problem because to get to the waranty dealer my friend has to travel 350 miles (thru the Mojave desert) from the lake house to his home. Breaking down on the way would not be fun.

 

[Almeja]

Re: wet hubs boiling

Some thoughts:

I've seen disk brakes stick and drag due to corrosion in the piston bores. The more they heat up in use, the more they drag... more they drag, the more they heat. Unfortunately, they may not display this behavior when completely cooled off.

Also If the wrong type of master cylinder is installed disk brakes can build back pressure and start dragging.

Were the disks really hot?... they should have been noticably hot to heat the bearing hubs up to boiling... if they are the cause

How heavy is the boat?
Lots of stop-n-go and/or downhills?

Begin Rant:

Brakes are typically rated for the load of the single axle they are mounted on... dunno why they put a single set of brakes on a double axle trailer. It is 50% under-braked to start with. My single axle brakes used t get really hot (boat/trailer is a 4 ton load)... I upgraded to brakes on both axles, no problems.

End Rant

IMHO: The bearings will have to be seriously shot to build up that much heat in a 10 minute drive... but it's entirely possible.

 

[dingbat]

Re: wet hubs boiling

Brakes are typically rated for the load of the single axle they are mounted on...

Where can I find the ratings for the various brake assemblies?

 

[bruceb58]

Re: wet hubs boiling

My guess is that a drum master cylinder was installed instead of a disc type.

I second Almeja's rant. My trailer which is rated for 7,000# only came with brakes on one axle. I just added brakes to my second axle. My last trailer, which came with a Bayliner, was only rated for 5000# but it came with brakes on both axles!

 

[cgBosun3]

Re: wet hubs boiling

I had the problem of the pistons sticking; I could hone the bores once and use oversize calipers, but that only woked once. This was back in the '80s and I think the mfr's got things right since then. But my brakes would stay on and it felt like the trailer had no wheels at all! The bearings were not affected nor the spindles.

 

[bruceb58]

Re: wet hubs boiling

One more thing...if the brakes got really hot once and warped both rotors, you could have a constant overheat problem after that. Might be worthwile checking the rotor runout, especially if they are non-vented rotors.

 

[bucky7680]

Re: wet hubs boiling

Thanks guys. It turned out to be a bad master cylinder that was sticking. The dealer sent out a replacement My buddy and I will be replacing it this weekend. The dealer also sent out new caps which are metal with a plastic window instead of all plastic. If he still has problems with the wet hubs I see that Bearing Buddy has a screw in model which alows retrofiting to grease hubs.

 

[DJ]

Re: wet hubs boiling

Bucky,

Find the problem and stick with the wet hubs. They are far superior in every way.