Disc brake discussion

[dznf0g]

Originally Posted by slowmover

The test of trailer brakes is how well they can stop the combined rig with no use of tow vehicle service brakes.

True, and I would add, how smoothly each of four (or two, or 6 depending on axle #) apply braking force in a linear progression all the way to lock up equally, and consistently over time.

IMO, and experience, that is difficult with four different friction surfaces for the magnets where that surface has, to a high degree of probability, different wear patterns. Add to that, constantly battling voltage differences between each wheel due to wire chafing, flexing and fatiguing, and corroding.

Been there done that. They work fine, but they are maintenance pigs to perform at 100% and equally over and extended time.

I'm not trying to be difficult, even with the stuff we complain about with the E/H (because for the money they should be as maintenance free and as dependable as car brakes) they are a lot less trouble than electric drum brakes. We accept a lot more maintenance/repair issues with drums because they are what they are and require care and feeding. Discs shouldn't.

If electric drums are so good, why aren't they on cars?

[AtomicNo13]

Slomover, then e/h trailer brakes are the way to stop!
I knock my head against the windscreen daily!

[SteveH]

Electric drums are on trailers because they satisfy the law requirement and they are cheap.

However, I'm not at all satisfied with by E/H drums either.

[J. Morgan]

How much more stopping can a brake accomplish beyond providing enough stopping power to lock the wheel?

Like I say, disk hyd are best, but s for me, well maintained electrics are more than adequate.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[SteveH]

I'm not dissatisfied because of the stopping power, it's great.

I'm dissatisfied with the delay, and the two failures I've already had in one year.

[dznf0g]

Originally Posted by J. Morgan

How much more stopping can a brake accomplish beyond providing enough stopping power to lock the wheel?

Like I say, disk hyd are best, but s for me, well maintained electrics are more than adequate.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

None, but that's not my point. Drums are more likely to individually prematurely lock up and more prone to individually not function without more frequent maintenance and repair, which we all accept as normal for the animal. We don't accept it on E/H because we expect them to behave and have low maintenance like our cars.

[GCinSC2]

Folks,

Interesting discussions. I did my own hose reconfig and bled my brakes several times as my repairs evolved and alignment of the planets moved in and out of phase.

My only experience is with the 4 piston Dexter calipers.

I don't think Dexter is to blame for the bleeding issues, Airstream attached with a flare fitting hose that really does not have easy provisions for bleeding, attached thread has before and after pics of my old hose vs. my combo line of hose and steel line that allowed pretty easy inboard bleeding of the 4 calipers which I see as critical to having any reliable chance of bleeding the system which is an absolute factor to any delay discussion.

As I have no experience with standard electrical brakes, can't make any comparisons.

Just as a sidebar to EOH I have to back down a hill in my yard to park my trailer. Very slow, blind side thru some trees into a carport. It requires a lot of braking modulation. The MaxBrake actually increases or decreases the system PSI just off of my trucks brake system pressure, you hear the load on the actuator.

This has a short video clip and pictures of my rework and my commentary.

http://www.airforums.com/forums/f439...ime-96724.html

I feel my rig's brakes are unified and much more than adequate and since my last efforts are untouched for any rework.

I'm not trying to convince anyone to change, but if you have EOH and feel you have an unacceptable delay, I bet it can be fixed.

Gary

[slowmover]

I've read that one of the reasons we didn't have disc in the 1970s was that Airstream held up development through patent monopolization (wrong terminology perhaps). There isn't any questions as to superiority. Electric drums are out of adjustment ten minutes down the road from service and are thoroughly inadequate for repeated stops.

So the delays and tech problems of discs are understandably a barrier for most. But this changed with the TUSON anti-lock module. Now there is no good reason to avoid disc any longer.

Gary's thread is excellent. And there some other threads on here about antilock and discs. So, too, the TUSON antisway module.

Better tires are the right step as are better brakes.

[J. Morgan]

I don't think that properly working drums are really more prone to lock up.

In my experience most lockups occur when moving at low speed in a turn when a motion actuated brake controller is caught "off guard". This happens about equally with elec or elec/hyd.

There is no real delay with my electric brakes, and whatever tiny delay there might be is equal whether elec or elec/hyd.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[J. Morgan]

One reason for some people to avoid disk/hyd brakes is cost.

My brake adjustment lasts 3,000 miles easy, every time.

While it can be argued that electric trailer brakes are "old technology", so are bumper mount trailers.

As I said above, Hyd disk brakes are great, but elec drums work well. I never worry about them any more than I would hyd brakes.

1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[dznf0g]

Gary, I recall us having some discussion (I think) while you were working your analysis. I do think there is one issue that is a Dexter design issue. A bleed point in a any caliper must be at the highest installed point in the fluid cavity in order for air to accumulate there and be readily pushed out. On the inboard caliper, I ASSUME the line is the highest point. But using the same orifice to admit high pressure fluid and remove air is problematic. If you crack the line as you would with a bleeder, the extremely fast inrush of fluid under pressure will break up the air bubble into many many small bubbles and distribute them throughout the fluid cavity.

I have tried, as I stated above, to loosen the line barely (at a weep volume) to hopefully keep the air bubble at the line port and have a better chance of pushing it out.

There needs to be a bleed point, higher than the line inlet, located away from the line inlet on the inboard caliper half....OR the cross over line should be on the top of the caliper, not the bottom.

[GCinSC2]

Rich,

Agreed, in a perfect world the inboard caliper half would have an independent bleed screw. Then Dexter would have to make sure the inboard caliper half gets the bleed screw.

OR a hose fitting design than Incorporated a bleed port somehow.

On a professional basis, I deal with air bubbles in small displacement clutch hydraulic release systems throughout the day helping our customers troubleshoot their systems, tiny air bubbles = big problems.

J. Morgan,

I'm not trying to convince anyone to install EOH, only really want to help anyone explore getting the most out of their EOH system but ain't nobody gonna convince me to convert to magnetic brakes. And having a pressure transducer based controller is just icing on the cake to controlling 16 pistons.
I had a non-compatible EOH installed by my dealer and backing down my hill it was pretty much all or nothing cause the hill was messing with it in addition to being non-compatible with EOH.

[Ag&Au]

Originally Posted by dznf0g

None, but that's not my point. Drums are more likely to individually prematurely lock up and more prone to individually not function without more frequent maintenance and repair, which we all accept as normal for the animal. We don't accept it on E/H because we expect them to behave and have low maintenance like our cars.

What's the frequent maintenance and repair? Maybe, mine are neglected, because I don't do any. I have Nev-R-Adjust brakes and Nev-R-Lube hubs. What else is there?

Ken

[wkerfoot]

The late 1970's trailers did have disc brakes, but only in the longer, ie 31 foot trailers. They were vacuum operated from the engine.

Bill

Originally Posted by slowmover

I've read that one of the reasons we didn't have disc in the 1970s was that Airstream held up development through patent monopolization (wrong terminology perhaps). There isn't any questions as to superiority. Electric drums are out of adjustment ten minutes down the road from service and are thoroughly inadequate for repeated stops.

So the delays and tech problems of discs are understandably a barrier for most. But this changed with the TUSON anti-lock module. Now there is no good reason to avoid disc any longer.

Gary's thread is excellent. And there some other threads on here about antilock and discs. So, too, the TUSON antisway module.

Better tires are the right step as are better brakes.

[Bill M.]

Am looking at getting new axles for my trailer and am considering whether to stick with the drum or get disc brakes so I am reading carefully.

Another question: I camped next to a fellow Airstreamer who spent a half day under his fairly new trailer changing a caliper on a disc brake that had seized or jammed or something and locked the wheel, causing a great deal of heat and smoke. He said that this was the second time that this had happened on his trailer. Is this a common occurrence? I have read that if disc brakes sit for a long time the slides for the caliper can get rusty and cause them to drag. Is this a common problem for disc trailer brakes? I had a caliper lock up on my old truck last year, possibly from a failed hose they said that did not let the caliper release pressure. Would not want that on a trailer.

[dznf0g]

Originally Posted by Ag&Au

What's the frequent maintenance and repair? Maybe, mine are neglected, because I don't do any. I have Nev-R-Adjust brakes and Nev-R-Lube hubs. What else is there?

Ken

Nev-r adjust certainly reduces maintenance...in theory. Really, not too many folks in RV land have them. The problem then becomes lack of inspection and cleaning. One advantage of discs are the fact that they are self-cleaning, or shed their brake dust. Drums capture and hold brake dust---all over the backing plate, etc. Unless the BEST of materials are used, particularly for the self adjustment barrel and screw, they become ineffective and stuck. So regular drum removal is still necessary. Compound that with the owner's feeling of "nev-r-touch" convenience of Nev-r-lube and the drums nev-r-come-off....until something isn't working very obviously.

Discs can be thoroughly visually inspected every tire rotation without any dis-assembly. There are no adjustment mechanicals, no hidden parts, pads can be inspected through the back of the caliper, friction surfaces can be inspected, Nev-r lube bearings can be inspected for feel and excessive clearance without dis-assembly. (arguably, so can drums, except the shoes can interfere with that "feel").

To address the other post about calipers becoming stuck.....not multi-piston calipers where pistons are on both sides of the rotor. On those, the caliper is fixed and all motion is in the pistons which compress each pad independently. Single piston calipers slide on the knuckle, or hub flanges. If those sit for an extended period (like years), they can stick and cause heat and wear to the outboard pad...but it is pretty rare even for those of us who put up the AS for the winter. Again, an easy inspection during tire rotation. Also, with hydraulic brakes all pistons get equal apply pressure, always, until they get really old and the interior of the rubber line deteriorates. then you could get some flow issues.

I was ALWAYS chasing voltage and high resistance variations with electric brakes. At least every couple years...due to wire breakage/fatigue, corrosion, abrasion, etc. Without that maintenance, you get unequal braking apply and apply force. Add to that, unequal wear to the magnet friction surface and eventually shorted magnets, and you have a lot more maintenance and repair. At least that's been my personal experience thus far.

[J. Morgan]

Originally Posted by GCinSC2

J. Morgan,



I'm not trying to convince anyone to install EOH, only really want to help anyone explore getting the most out of their EOH system but ain't nobody gonna convince me to convert to magnetic brakes.

Where did you see me say that a conversion to magnetic brakes is something anyone should do?

I simply stated that electric brakes are more than adequate for a trailer like an Airstream.

I like Disk trailer brakes. I bought my first trailer equipped with disk hydraulic brakes in 1990. This trailer when purchased used vacuum/hydraulic control which I later changed to elec/hyd.

In the years since I have purchased over a dozen other trailers with disk brakes, and some with drum. The ones I have bought are great systems, I like them a lot, but their are still places where electric brakes work fine.

1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

[Inland RV Center, In]

Originally Posted by dznf0g

Nev-r adjust certainly reduces maintenance...in theory. Really, not too many folks in RV land have them. The problem then becomes lack of inspection and cleaning. One advantage of discs are the fact that they are self-cleaning, or shed their brake dust. Drums capture and hold brake dust---all over the backing plate, etc.

Nev-r adjust electric brakes are far superior to those that must be adjusted.

Regular electric brakes should be adjusted about every 2,000 (two thousand) miles, to keep them at their maximum braking power.

All that's needed to keep the nev-r adjust electric brakes at maximum braking power, is back up the trailer a few feet every 1000 to 2000 miles.

Yes, they cost a few bucks more, but they do indeed satisfy the brain far more than regular electric brakes.

Unfortunately, most owners with standard electric brakes, do not have a clue that they should be frequently adjusted, to provide maximum braking power. Most owners wait until the magnets need replacing at 25,000 to 30,000 miles or less, and then most shops would still not adjust the brakes, because if you ask them how, they will hym and haw about the correct procedure.

Therefore, installing the seld adjust electric brakes, pays many many dividends.

Then of course, as this thread had talked about, we have disc brakes. Some opinions disagree that they are superior, but the cold and hot facts are that they are superior in every way, than electric brakes, self adjusting or not.

If they were not superior, then why do most cars and small trucks today have them???

The discs are cheaper to maintain than electric could ever be.

Disc's do not fade, as electric brakes do.

The only large difference in price, is the cost of the disc actuator.

Yes there are some good disc systems and some that are just fair. A reputable Airstream parts dealers, most always strive for the best. Yes there are a couple of new dealers, that are basically mindful of the customers pocket book, as opposed to top performance of the parts they sell.

A dealers reputation, when it comes to things like disc brakes, is something that each potential buyer should consider.

No dealer is perfect, but there are a few that constantly strive to be "top notch".

We feel that potential upgrades to disc brake buyers, should carefully do some home work, to assure themselves that they are making the correct decision, as best they can.

Price alone, is not the only consideration to make.

Be happy and always strive for the maximum in safety.

Safety is cheap, when the negative alternative happens.

A well informed Airstream or Argosy owner, will always be at the top of the "big smiles list".

Time after time, that has been proven to those "smiliers".



Andy

[ROBERTSUNRUS]

Hi, if you want your trailer to stop every time, keep the drum brakes. If you want your trailer to stop better, when they work, change to disc brakes. If, and when, they make disc brakes that work as well as my Lincoln Navigator brakes, or any other automotive brakes, I might consider them. Right now disc brakes on Airstream trailers are a Mickey Mouse, Hong Kong, after market nightmare. And many comments on this thread prove it.

[J. Morgan]

The trailers I have primarily use 10,000 pound Dexter axles with disk brakes, they have been very reliable, especially once I switched to Dexter actuators.

The primary issue I have had is that two 30 amp circuits are required to reliably operate the actuator, one from the battery, and one through the brake controller.

Most of my road failures have been because of a failure of one or the other of these circuits.

The wheel units have been perfect. I have never had to replace a rotor and ALL of my brake pads have lasted for over ten years.

If AS cant do this with their systems, (or aftermarket) then they suck, and they aren't trying hard enough.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow