Dexter hydraulic disc brake problem

JR

JRoger-TC

Member
Joined
Dec 16, 2004
Posts
21
I guess this is an "exterior" related problem!

There was a recent post on the Yahoo Mobile Suites forum the someone that had a problem with the pad keeper bolt coming out and causing the pad to drop out then the calibpers causing damage to the disc, etc.

I checked mine on a new MS 38RL3 and found one bolt that has lost its nut and tried to back out but was stopped by the aluminum wheel, so far. Eventually the bolt would have broken and the pads would have fallen out. Luckily all I have is a slightly scored wheel.

Anyone with Dexter disc brakes should check this immediately.

If anyone has other "voices" it would be good to share this info.

Thanks!
 
Didn't he say the failure was due to the bolt being cranked down to tight causing the failure? That Dexter has made a modification using longer bolts so that they can't be cranked too tight anymore?
 
Yes, that was his statement. I found that my pad keeper bolts were apparently of the new/shoulder type but still one of the nuts came off. If they can come off after the relief solution, they still need watching. I have contacted Dexter about a replacement nut. The nuts are a locking type but if they can come off, there is still a problem.

Thanks for helping clarify this issue.
 
Well, wonderful. Sounds like the problem still isn't fixed. Here I thought we'd be OK since ours will an 05.
 
I have some questions. Where are these bolts? Does the wheel need to be removed to see them? If so and you have your wheel off can you send a picture. Is dexter going to do a recall. Is this occuring with all the disk brakes from Dexter or is it only with the MS. I had my disc brakes installed by MorRyde a year and 25,000 miles ago. As of this time I have not had a problem. Am I now immune to this problem or do I need to take everything apart?
 
From comparing the disc brake types on the Dexter web site, it looks like this is unique to the 8K axles. These disc brake units have a fixed dual pad system that uses one 4 inch by 1/4 inch bolt with 10/32 threds and a self gripping/slotted nut to hold both pads in place. The bolt is inserted from the outside with the wheels off and the nut is screwed on. The bolt and nut can be seen from under the unit and looking at the pad housing. The bolts with the shoulder can be moved back and forth slightly. Apparently the non-shoulder bolts were tightened down and then broke from the expansion/contracting from use. The fix for them was to loosen the nut one turn to allow space for expansion, etc.

You can see these units on the www.dexteraxle.com web site in the 8K brake kit. The pad keeper bolt is shown but not listed as a separate part number. Other Dexter disc brake units don't seem to use the pad keeper bolt system.

I don't know Dexter's position as I just learned of this on the Yahoo Mobile Suites forum today.

Out unit is an 05 with the shouldered bolts but the nut still has a tendency to come off for some reason. I'm not sure what the official long term fix should be except that I will take a pair of vice grips and smash the threads on the bolts to keep the nuts from coming loose.

The aluminum wheel has sustained some scorring but is not ruined. The bolt would probably broken soon.
 
OK, the link worked. The pad keeper bolt appears on the lower left of the parts picture.
 
Disc Brake Problem

Roger: The system looks straight forward but I am not impressed with the hydraulic crossover line being at the bottom of the caliper halves. I noticed the retaining bolts are kind of small diameter for this application and have a question. Are the locking nuts of the Nylon insert variety? The heat that may develope and the stretching the bolt may be exposed to could dictate the use of double locknuts instead of the ny-lok variety. Oh well, that's just one more thing to modify after taking delivery. My D/W says I look for stuff to keep me busy while lazing away the winter in the south.
 
The nuts are not the nylon lock type. They are all metal with several slots to make a grip lock. Obviously something needs to be added to prevent them from coming off.

You are right about the bolt being small.

I have an email into Dexter on this.
 
After looking at the pictures of the 6K, 8K, and 10K brakes on the Dexter web site, mine look more like the 10K brakes. They look nothing like the 6 & 8K brakes with the open top and 4 hex head end bolts.
 
Hmmm, I didn't know they were using anything heavier than the 8K setup.

Mine look like the 8K units.
 
JRoger, mine are on my current trailer. I had them installed at MorRyde last May. I suspect that the current 6 & 7K brakes are of a new and superior design. For example they now have pistons on each side and the shoes can be replaced without disassembling the brakes. This relatively minor issue of the bolts will be solved quickly.
 
rverdlm, I hope you didn't mean what you said about the "minor" issue with the bolts. What started this topic was an owner losing his brakes entirely when the brake broke on his rig because of an over tightened bolt.
 
I certainly didn't mean it was minor when the brakes failed. What I meant was that as an engineering issue it was minor to fix and that when fixed the system appears to be an improvement over the ones I have. Also for those with these brakes it will not be a major issue to have a repair made. For a fulltimer like me the thought of loosing the use of your trailer for any lenght of time is a major issue.
 
OK. Must have been the way I crossed my eyes when I read the statement about minor. :D
 
FWIW the use of a nyloc nut is not a good idea in a high heat environment like brakes. A steel lock not (the type with "fingers" on the outside edge) is a good idea. It should not loosen as long as there is a washer beneath the nut in case the bolt rotates. Steel lock nuts are a fairly common item in aircraft uses and have a very good record in my experiance.
 
Today, after talking with Dexter Axle about the "brake bolt issue" on
our Mobile Suites, I checked the bolt in the disk brake mechanism to
determine if it is the new desirable one, or the old "putrid" one.

Looking at the back of the brake/wheel----I found two c. 3/8th inch
bolts at the upper end of the calipers, and two c. 3/8th inch bolts
at the lower end of the calipers.

Exactly between the two pairs of bolts, and near the outer edge of the
calipers, was a c. 1/4 inch bolt that was loose or movable. In other
words it will wiggle, or move back and forth/mostly in and out,
about 1/8th to 3/16th if one pulls on the nut end. It moved easily.

Dexter said if the bolt moved easily, I have the newer version and
should not have the problem some people have reported.

The axle has a number stamped in the center of the axle tube, midway
under the trailer. Our axle number is #112343622. I suspect the numbers
are sequential, so you might be able to guess when your chassis was
built at Dexter by comparing numbers. According to Dexter, our trailer's
Dexter chassis was built on Aug 24, 2004 and the completed trailer was
picked up in mid-September 04 at the dealer.
 
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