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Mike S. · 10-29-2016, 03:03 PM

Can I ask a favor? If you haven't installed the new parts yet, could you measure the thickness of the magnets? When I asked Dexter, they could only provide a minimum thickness when new, which was .700 inches. Thanks in advance, Mike

perryg114 · 10-29-2016, 04:10 PM

What is the min thickness?

Perry

Wingeezer · 10-29-2016, 04:16 PM

Quote:

Originally Posted by perryg114

What is the min thickness?

Perry

The old magnets I removed had small holes (maybe 1/8" diam.) drilled into the face to a certain depth as "Witness" holes.

When the magnets have worn to the point that some or all of the holes have vanished due the wear of the surface, that is the indication to change the magnets I believe.

They principle is sort of like the wear bars on tire treads only in reverse!

I don't know if all brands of magnets are made this way though.

Brian.

Mike S. · 10-29-2016, 04:22 PM

That's what I was trying to ask but they couldn't or wouldn't say. Etrailer said to change the magnets when the coils had worn thru and contacting the drums. Not really the answer I was hoping for.

perryg114 · 11-05-2016, 07:38 PM

Well it looks like etrailer is going to let me down. It has been a week and they are telling me that the parts won't even ship till the end of the month and I need to have this done by the end of the month. I guess they are ordering parts from China. It is silly to expect someone to wait a month. That is not an in stock item if it has to come on a slow boat from China. So one week wasted already. I can get the drums locally but the self adjust backing plates I will have to order. I hate adjusting brakes. I had enough of that with my VW. GRRRRRRRRRRRRRRR.

Perry

tjdonahoe · 11-06-2016, 08:03 AM

Too bad , Ratco , a trailer supply here, has them on the shelf....

perryg114 · 11-06-2016, 08:10 AM

I can get manual adjust backing plates and drums here but the auto adjust they don't have. I can probably get them from Amazon in time.

Perry

perryg114 · 11-06-2016, 08:19 AM

You have specific links on the down side to self adjusting brakes?

Perry

Quote:

Originally Posted by slowmover

Reports on WOODALLS a few years ago was that the self adjust may not be so great. See threads by JBarca as those are an impressive tech resource.

1990 35' Silver Streak
2004 555 Cummins

tjdonahoe · 11-06-2016, 09:55 AM

[xQUOTE=perryg114;1873290]You have specific links on the down side to self adjusting brakes?

Perry[/QUOTE]

Well all our cars and trailers have them...and they work really well

slowmover · 11-06-2016, 01:41 PM

Quote:

Originally Posted by perryg114

You have specific links on the down side to self adjusting brakes?

Perry

Look up Johns post on WOODALLS under, "Dexter Self Adjusting Brakes". From 2009.

I believe you'd like all of his threads.

Best tech on the web when he does up a thread. While the leaf spring tech isn't applicable to most AS, the other threads on WD hitches are always good.

(Off topic: ran thru your town a good number of times last year. Decatur to Guntersville. A long slow narrow residential hill climbing out of Huntsville with a 60k tanker, ha! Or cross country to Chattanooga. Beautiful area.)

1990 35' Silver Streak
2004 555 Cummins

polarlyse · 11-07-2016, 02:17 PM

I have self adjusting brakes on our Airstream. They work well and I do like them. If I had to come up with a negative the only thing I could think of is that I am not forced to periodically take a close look and inspect the brakes and re-pack the bearings. I have to think about it and force myself to do it. But I still like and would vote for the self-adjusting brakes anyday.

perryg114 · 11-09-2016, 06:07 PM

Huntsville is pretty this time of year. Not so much this fall since the trees are turning brown from the drought.

Got my brake order from Southwest wheel but they left out the bearings and bolts. Hopefully my old bearings will fit. I need to measure the spindle.

Perry

Quote:

Originally Posted by slowmover

Look up Johns post on WOODALLS under, "Dexter Self Adjusting Brakes". From 2009.

I believe you'd like all of his threads.

Best tech on the web when he does up a thread. While the leaf spring tech isn't applicable to most AS, the other threads on WD hitches are always good.

(Off topic: ran thru your town a good number of times last year. Decatur to Guntersville. A long slow narrow residential hill climbing out of Huntsville with a 60k tanker, ha! Or cross country to Chattanooga. Beautiful area.)

1990 35' Silver Streak
2004 555 Cummins

perryg114 · 11-12-2016, 07:07 AM

The bearings and other bits came the next day, so I have all my parts, Southwest Wheel came through. They could have packed the bearings a little better. They were loose in a box with a bunch of other stuff. I ended up using the new Chinese bearings. These drums are 6000 lb rated with a bigger outside bearing than my old drum so there was not using them over. The axels are rated at less than half the rating of the spindle and bearings.

One good thing that Airstream did was over spec the axle and brake components. I figure even the Chinese bearings will be fine at these loads. I will keep an eye on them and measure temps with my IR thermometer although a hand is just about as good.

I have two wheels done and have the bearing and seals done on the other two drums. The hardest part is getting the old backing plates off with rusted POR15 encrusted bolts with self locking nuts.

I think the magnets were weak on my old brakes. They mechanicals looked fine. I tested the new brakes and they lock. You can hear the magnet snap onto the face of the drum which I never heard with the old brakes. I got self adjusting brakes which I am hoping will keep them all even with each other and prevent them from being too tight and dragging.

My spindles on my 31 ft 81 Excella II are 2.25" inner seal, 1.75" inner diameter and 1.25" outer diameter. I think these are called 6000lb spindles. I think the 5200 lb drums where what was on there. I think the slightly bigger outer bearing makes them 6000lb. Again the bolt pattern is 6 on 5.5". Everything seems to fit just fine. They sent 2.125 seals as well and two different types of grease caps. One was solid and the other has the rubber plug for the easy lube axles with the grease fitting in the end.

Perry

perryg114 · 11-13-2016, 08:30 AM

Ok it is done. Southwest Wheel got me the parts in less than a week with about $25 more than Etrailer. Worst part was removing the bolts that held the old backing plates in. I did not measure the magnet thickness. There are little holes in the center section of the magnet. I would replace the magnets when those are no longer there or the magnet is no longer flat. The force that the magnet creates when it sucks up against that drum face really depends on everything being flat. As soon as you have a gap between the magnet and the drum face the force is doing to go down. If the drum face is worn really bad, replacing magnets may not help that much. It is possible to turn that face but then the magnet has farther to move before it attaches. I am not sure how much you can take off and things still work. I may go with 16 inch rims next time around and convert to disk brakes.

Perry

slowmover · 11-25-2016, 03:57 PM

Look forward to your road test. Can't remember your brake controller brand, but your TV may be old enough that minor brake switch modification brings on faster TT brake actuation. See BenK on WOODALLS in 2010 thread, "Intermittent trailer brakes effecting [sic] tow vehicle".

Dad and I "blueprinted" the same on his tow vehicles way back when.

1990 35' Silver Streak
2004 555 Cummins

perryg114 · 11-25-2016, 04:22 PM

The road test went well. The trailer brakes will actually stop the tow vehicle as well. The voltage to lock went way down to about 4V which concerns me a little. I am using a Techonsha PII which seems to put out full voltage just before you come to a stop which contributes to the lock up problem. I don't think electric trailer brakes are at all linear. I am thinking you get almost full braking when the magnet sucks up against the drum face. So maybe you are getting 50-100% and then nothing prior to that. Drum brakes are not very linear even when they are hydraulic. I expect things will need a few hundred miles to break in. None of them seemed to hang or drag like my old ones did when adjusted properly. I got the auto adjust which should keep the braking consistent. I need some shim washers for getting the preload right. I had my old washers and the new ones and was able to get close by swapping out washers.

I could not use my old bearings. They were smaller than the ones the drums came with. I think the new ones are 6000-7000 lb bearings.

Perry

slowmover · 11-25-2016, 04:51 PM

Which locks first would be my next concern. An observer in a chase vehicle would be good. Which locks first, and which side. On pavement and on loose.

I also believe in maximizing TW transfer to TT (up to one third) as part of best braking performance. Full pressure in TT tires, and adjustments per scale readings.

"Linearity" is part of brake controller capability. Second tier controllers like the P2 and 3 are "best" (IMO) set up for earliest application (brake switch mod). The "best" controller these days is the DirecLink. Assuming "even" brake performance, it'll be better about graduated performance. Although it usually takes a heavier trailer than an AS to notice.

1990 35' Silver Streak
2004 555 Cummins

perryg114 · 01-28-2017, 05:37 PM

First trip to FL with the new brakes and they work great. Still running at a little over 4V. The brakes are a little grabby just before a stop and for some reason that is when the TIII puts out max voltage. We drove 650 miles in 12hrs in heavy rain and the rig handled well. I have learned to back off the brakes just before stopping to reduce the harshness of the trailer brakes. I am not at lockup but it seem to be at a good place. I expect that I would turn up the voltage if I were in the mountains.

The brakes did not drag at all like my old brakes did. I like the self adjusters. It takes the worry out of it and never having all 4 wheels adjusted the same. It was a good investment and long overdue.

Perry