PDA

View Full Version : OK Guy's My Turn !


Restrorob
08-07-2007, 07:02 PM
Hey all,
We have a tandem axle goose neck for our larger rental equipment. The driver has been complaining about the brakes not working properly.

It has two 10,000 lb. axles, The first things I checked was the controller and made sure I was getting power to all electro magnetic pads which were fine. Then I pulled the drums to inspect the linings which wear wise looks like they just came out of the box.

Here is my questions using the picture below;



http://i107.photobucket.com/albums/m314/Restrorob/ElectricTrailerBrake.jpg


When the brake is applied the electro magnetic pad grabs the disc inside the drum and moves the arm to the left to spread the shoes to apply the brakes since there is a stop tab keeping the arm from moving to the right.

Is this the proper function of these brakes ?
If not could you explain ?

Thanks For Any/All Input....

fly-4-fun
08-07-2007, 07:23 PM
Did the problem just start or has it been a gradual decrease in the trailer brakes?
If it is a gradual decline, then I'd say to adjust the shoes out. Trailer brakes are not self adjusting like on a car and if they aren't adjusted ever so often the shoes can't expand enough to grab the drums.

Restrorob
08-07-2007, 07:46 PM
Sorry fly-4-fun,
I failed to mention we do keep the shoes adjusted and the adjustment was fine today before tear-down.

I just need to know if they function as I figured they do in my above post.

Thanks

tomo
08-07-2007, 09:03 PM
hello it would appear to be the correct method of operation for that brake set up .As u can assume this is over the web so i cannot see in detail the mechanisms to evaluate properly .
As u may be aware u can have the shoes radius ground ,to the exact fit to the drum . Even when u think it will be ok radius grinding shoes ensures 100% contact to drum .
New drums?? if not are the drums past there max limit for machining max diameter]
The contact surface 4 the magnet is it grooved etc ?? replace magnet and either machine surface or replace drum
U may be aware that braking systems can have a leading and trailing brake shoes [depending upon design] when they are reversed performance can suffer . Eg a pickup truck range at a dealer required the shoes to be reversed so to decrease max braking and to avoid locking of brakes when unladen .

tomo:waving:

ps short linning to front ,picture seems back to front ,rotation of wheel is clockwise so short is trailing ,this raises questions ??

ps2 Rob did u receive the pm with model type chassis etc??

fly-4-fun
08-07-2007, 10:33 PM
Electric brakes are actuated electrically through a magnet rather than hydraulically through a wheel cylinder. The magnet is positioned so its poles are close to an armature surface, which is machined or bolted inside the brake drum. When the magnet is energized, it is attracted to the armature surface causing a frictional force that pivots the lever arm and slipper block. This forces the primary shoe against the drum which energizes the secondary shoe.

fly-4-fun
08-07-2007, 10:45 PM
Here is a site that has an animation of how it works.


http://www.al-kousa.com/prod_bhd.htm

Restrorob
08-07-2007, 10:49 PM
Thanks fly-4-fun, That's what I was looking for.....

Also read below;



ps short linning to front ,picture seems back to front ,rotation of wheel is clockwise so short is trailing ,this raises questions ??
ps2 Rob did u receive the pm with model type chassis etc??

tomo, You didn't get my PM I sent at 8:47 ?




The drums show no sign of a wear lip where the shoes don't touch and the E/M disc looks fine.

The shoe length is only one of the questions......

Here is a paste, I have this posted elsewhere also.

---------------------------------
This trailer never really stopped well from day one, We have had it around 10 yrs. and I don't recall ever putting shoes on.

If these brakes function as I posted above and the E/M pad moves the arm to the left to spread the shoes with the tire rotating clockwise that would mean the above brake assembly would need to be on the right side correct ?

Here is what I'm getting at;
The brake assembly above (pic) is on the left (driver's side of the trailer). Therefore when the E/M pad is activated it grabs the disc inside the drum but can't spread the shoes because the arm is against the stop tab.

So my theory is the guy that put the axles under this trailer had a couple six's too many the night before and put them in back-wards. If this is so all we've had is what little braking the E/M pads were doing. This could explain 4
brake jobs on two trucks.

When the manual lever on the controller is slid all the way over to engage shouldn't it Lock the wheels up tight ?

When doing this I can pull off without hardly any drag.....

Thanks

Restrorob
08-07-2007, 11:00 PM
Here is a site that has an animation of how it works.


http://www.al-kousa.com/prod_bhd.htm

I just seen this after posting, Boy am I confused now !

The arms on our trailer don't move like the little animation but the other direction :confused:

Guess I'll take a closer look tomorrow and see what the heck is going on.....

Thanks

khouse
08-07-2007, 11:10 PM
Maybe the brakes and backing plates were installed on the wrong sides? Also the larger lined shoe goes to the front. The front shoes are thrown into a binding action and need the extra lining.

tomo
08-08-2007, 12:28 AM
Rob , as i mentioned earlier the shoes seem not correct at first at the start of the story .

As we continue the plot thickens .If u notice on the backing plate there seems to be a brand maybe eg """"DEXTER""", well what ever it may be find the maker and make a few calls . Another theory is the original installer had both sides dissasembled and mixed the parts some LH and some RH together on same side . Seen all this b4:hammerhead:

Check controller install as per maker they all have there own install particulars .Please donot make any general assumptions . Some controllers are fairly poor and seem to have a troubled history . Others like the prodigy and the better one again the P3 seem to be state of the art . Another valid point is the P3 can have the initial setup be at a certain percentage of brakeing eg 10--30 % .This applies as the trailer becomes large in comparison to tow vehicle .

All this came after investigating brakes for my new trailer .
HaHa ,i went down the road of hydraulic disc activated by over ride coupling with max legal gross weight of 4500lbs ,simple setup .
Over 4500lbs i must be electric or air all wheels

tomo:waving:

Restrorob
08-08-2007, 12:29 PM
OK, Further inspection shows the E/M pad arms are stuck. This is why I couldn't move them the proper direction, Also the E/M pads are worn un-even.

We are going to clean all brake assemblies up and apply a little white grease to all moving parts and install new E/M pads, Hopefully this will solve the problem.

Thanks everyone for your replies !

olyman
08-08-2007, 03:49 PM
resto--also make sure the wire to the brakes is at least 12 gauge--esp if both axles have brakes--been there--14 might be ok for one brake--but not for two---it takes current and amps to set those brakes--but it sounds like someone has those brakes totally screwed up!!!!!!!! get a pic of the way they are supposed to be from where you get the parts for them from--they have them-------with a hub off--have soemone pull the brake controller--and see how strong the magnet is--as these sometimes weaken over time--who knows why??? the harder the mag pull---the harder the brakes apply--

Restrorob
08-08-2007, 06:53 PM
with a hub off--have soemone pull the brake controller--and see how strong the magnet is--as these sometimes weaken over time--who knows why??? the harder the mag pull---the harder the brakes apply--

Strange olyman, That was a test I performed this morning, I wanted to see if the rheostat in the controller was acting up (not putting out enough voltage).

I took our 750 cca jumper battery and jumped right to the magnet. With a 3" putty knife held across the pad area I couldn't move the arm at all without it sliding off, I was able to pull the putty knife straight off pretty easy.

The new E/M pads should be in tomorrow and I'll perform the same test on them to see the difference.

Oh, The wire size appears to be larger than 14 ga leading to all 4 backing plates.

Thanks

olyman
08-08-2007, 08:37 PM
rob--thats what i call B A D magnets!!!!!!!!! you shouldnt have been able to pull them off with a dozer at full power!!!!!!!:) :) be careful to use a grease on the pivots points that doesnt draw dust--and i dont have to eggsplain why--i personally use antisieze--no joke--nickel based--it will get a light coating--but thats about it--and you know how sticky that stuff is!!!!!!!!!!

Restrorob
08-08-2007, 09:28 PM
i personally use antisieze

Yeah, That's a better idea. I had planed on using that on the adjusters since one of those had locked up since the last adjustment. The white grease came to mind because back in my auto biz days the boss was old school and that's what we used back then, But I believe a little smear of the antiseize will work better.

Bull Dozer Huh !!!

Thanks

olyman
08-09-2007, 07:59 AM
Yeah, That's a better idea. I had planed on using that on the adjusters since one of those had locked up since the last adjustment. The white grease came to mind because back in my auto biz days the boss was old school and that's what we used back then, But I believe a little smear of the antiseize will work better.

Bull Dozer Huh !!!

Thanks its realitive--accordinging to the size of the dozer!!!!!!!!!!!!!!!!!

Eric D
08-09-2007, 07:24 PM
Maybe the brakes and backing plates were installed on the wrong sides? Also the larger lined shoe goes to the front. The front shoes are thrown into a binding action and need the extra lining.

Khouse,

You have this 180 deg out. The shorter lining is always to the front of vehicle.

Regards,

Eric D

khouse
08-09-2007, 08:21 PM
Eric D,
It was 1984 when I quit working on cars. Thanks for keeping me strait. Maybe it was just too many beers!

Restrorob
08-09-2007, 09:28 PM
Well, Found out today my E/M pads wont be in till Monday.
The dang trailer has to roll tomorrow so gotta put it all back together as was, I HATE having to do things twice.....

I will post the results next week for reference.


PS, khouse....Don't feel bad, I get mixed up sometimes too and I don't even drink anymore !!!

olyman
08-14-2007, 03:53 PM
ok my turn--hows they working now?????????????:rolleyes: :rolleyes:

Restrorob
08-14-2007, 07:01 PM
Well olyman,

They don't.....I just got the new ones this evening, I did have time to do a little test before leaving.

I had left one of the old pads off when I put the trailer all back together.

I performed a resistance (ohms) test and the old pad was 3.8 and the new one was 3.7 .....I thought aw crap they still are not going to work after spending 400 bux.

Whipped out my jumper battery and putty knife again and re-tested the old one holding it in my hand and pulled the knife off, Did the same with the new one but it was a little harder to pull off. I really wasn't satisfied that these new pads were going to solve the problem.

I just sat there a minute thinking about it then decided to see if they were any stronger on a piece of metal that covered the full pad surface (which the putty knife didn't).

I hooked the old pad up and stuck it to the leg on my air table (I was sitting right there while testing) and was able to pull it back off with my hand, A little hard but could, Stuck the new pad on and well....That bulldozer would of came in handy, I couldn't get it to move.

I told my boss of this and he asked how one can be stronger than the other with such close resistance readings, All I could do is shrug my shoulders.

Can you or anybody else give some insight as to why/how ?

I spent some time on "How stuff works" but didn't find a answer.

Thanks

DiyDave
08-14-2007, 07:57 PM
I don't know the physics behind it, but a thin ferrous metal object will never give you the hold capacity that a thick piece of iron will. I have an electromagnetic drill press that is used for drilling through truck frames. It says right on the side of it not to try to drill through any iron less than 1/4" thick, as the e.m. won't hold on thin metal. You were right to test it on a thicker piece of metal that likely mimics the thickness of the brake drum.:waving:

khouse
08-14-2007, 09:37 PM
Maybe it's your flux capacitor! :laugh:

Restrorob
08-14-2007, 09:54 PM
http://www.ostfriesenpower.org/neues.htm/024.gif http://www.ostfriesenpower.org/neues.htm/e124.gif

fixer67
08-14-2007, 10:31 PM
Well olyman,

They don't.....I just got the new ones this evening, I did have time to do a little test before leaving.

I had left one of the old pads off when I put the trailer all back together.

I performed a resistance (ohms) test and the old pad was 3.8 and the new one was 3.7 .....I thought aw crap they still are not going to work after spending 400 bux.

Whipped out my jumper battery and putty knife again and re-tested the old one holding it in my hand and pulled the knife off, Did the same with the new one but it was a little harder to pull off. I really wasn't satisfied that these new pads were going to solve the problem.

I just sat there a minute thinking about it then decided to see if they were any stronger on a piece of metal that covered the full pad surface (which the putty knife didn't).

I hooked the old pad up and stuck it to the leg on my air table (I was sitting right there while testing) and was able to pull it back off with my hand, A little hard but could, Stuck the new pad on and well....That bulldozer would of came in handy, I couldn't get it to move.

I told my boss of this and he asked how one can be stronger than the other with such close resistance readings, All I could do is shrug my shoulders.

Can you or anybody else give some insight as to why/how ?

I spent some time on "How stuff works" but didn't find a answer.

Thanks

How many amps does the new ones pull? How many amps does the olds ones pull? Maybe heat damage to the old ones is the reason they are not as efficient at turning the power into magnetism. Just guessing.

olyman
08-15-2007, 12:01 PM
also--think of it this way--you have windings inside for the magnet----if theres very little resistance to begin with--if a wire shorts across inside--so that instead of having 300 windings--you now have 150--how much diff in holding power???? right---a whole lot less---same thing will happen in a winding for the charge circuit inside the flywheel---sometimes will short across----because some yo yo that made the wire--didnt get enough varnish on the wire--and it eventually shorts thru--:) :)--also--theres a diff in the composition of metals--putty knife not withstanding--and they all have diff magnetic properties---

Bill Kapaun
08-15-2007, 12:06 PM
Your putty knife may be some version of stainless steel, which has varying degrees less magnetism than iron.

Restrorob
08-15-2007, 08:11 PM
OK Guy's,

After more inspecting this morning this is what I came up with.

Here is the exact brake set-up I'm dealing with, It's made by Warner Electric.


http://i107.photobucket.com/albums/m314/Restrorob/TrailerBrake.jpg


The center core (in red) runs all the way through the pad and is flush on the back, The windings I'm guessing are wrapped on a plastic sleeve then this center core is bonded in place.

On the old pad this center core has pulled it's self (guess became un-bonded) to the outside and wore this core smaller. The core is up inside the back of the pad by 3/8".

With a smaller core in the center that would give less material to magnetize so would create a weaker pull ?

Doe's this sound feasible ?

Oh, The trailer is booked until next Thursday so that's when I may get a chance to install the new pads. The driver has been cautioned and is driving much slower with the weak brakes until we can down it again.

Thanks to everyone who has helped enlighten me on these electric brakes. http://forums.vr-zone.com/images/smilies/thumbsup.gif

rockytopp
08-16-2007, 12:22 AM
Restrorob,
I have a 24 foot roll back and it has the same dexter set up. I can skid all four wheels with 15 thousand lbs. on it. so you do have something not working. I have had to replace the electro magnets on two wheels. they do break down and lose their ability to function. this could be the problem, I have put brake shoes on mine once and I cannot recall the position of the parts. If you don't get a true picture as they should be installed I can pull a wheel and take a pic and post it for you. Rocky

olyman
08-16-2007, 08:53 AM
that core should not have come loose--junk for that one--when you get it back together--should be fine--oly

Restrorob
08-16-2007, 11:57 AM
If you don't get a true picture as they should be installed I can pull a wheel and take a pic and post it for you. Rocky


Thanks for the offer rockytopp, The new pads came with a complete break-down of the assembly.

************

If I keep playin around I may get as smart as all you guys on these things !!!

olyman
08-16-2007, 03:51 PM
If I keep playin around I may get as smart as all you guys on these things !!![/QUOTE]
tell ya what pal--there aint a whole lot you dont know--and this problem is a minor part of you repotuiore!!!!!!!!!!!!!:) :)

Restrorob
08-16-2007, 09:23 PM
Thanks olyman.......:o

olyman
08-18-2007, 08:49 AM
wellllll--sliding brakes yet?????????

Restrorob
08-19-2007, 10:02 AM
Naaa....No sliding yet;

The trailer is booked until next Thursday so that's when I may get a chance to install the new pads. The driver has been cautioned and is driving much slower with the weak brakes until we can down it again.


Maybe this Thursday/Friday he can go out and flat spot the tires.....:laugh:

olyman
08-20-2007, 07:41 AM
if the trailer sets more than 1 week---when i hook up--and going down the road a bit--i grasp the controller lightly--and let the brakes touch--why--because slight rust will get on the mag surface--by lightly touching the brakes--it knocks the rust off----in case have to hit brakes hard down the road-----instant bite-----

olyman
08-22-2007, 08:50 AM
i expect a reply on the trailer today---:) :)

Restrorob
08-22-2007, 12:22 PM
i expect a reply on the trailer today---:) :)


OK olyman, Here's your reply.......

Still no brakes.....No sliding.....Nothing......:cry:

Why ?????

I haven't put the new pads on yet..... :laugh:
It's on the docket for 8am sharp in the morning. :)

olyman
08-22-2007, 05:27 PM
:dizzy: :dizzy: dang kids---

Restrorob
08-22-2007, 05:57 PM
HAHAHA !
If you do have me it's not by much....:nono:

I can only wish I were a kid again. :cry:

Restrorob
08-23-2007, 09:51 PM
Hey olyman....

I got the pads on today but now I have a thump....thump....thump when going slow ???

Do ya think I should of turned the controller down before I snatched the manual lever over ? JK....

They are working great again http://www.ostfriesenpower.org/neues.htm/c014.gif

Thanks to everyone that posted and fly-4-fun for the animation link so I could see how the operate....:usflag:


Oh, Tomorrow I'm going to cut open one of the old pads to reveal the magnet, Just to see what it looks like. I will post a pic for anyone else wanting to take a gander.....

olyman
08-24-2007, 08:30 PM
[QUOTE=Restrorob;1940644]Hey olyman....

I got the pads on today but now I have a thump....thump....thump when going slow ???

Do ya think I should of turned the controller down before I snatched the manual lever over ? JK....

kids!!!!!!!!!!!!! glad to hear--have helped people over on another forum---they be happy when their working again!!!!!!! and i dont know how you set brakes---but i raise the axle--and tighten till they are rubbing the drums lightly---instant stop--which is what you want--and they wont get hot just touching the drums--plus after some stops--they will be seated to the drums--and wont be touching anymore---:) :) :) oh ----and tearing the magnets apart--just like a little kid--cant help yourself---can ya??????????????????

Restrorob
08-24-2007, 10:42 PM
Yep, That's the way I've always adjusted brakes. I adjusted then took it for a slide then re-adjusted.


oh ----and tearing the magnets apart--just like a little kid--cant help yourself---can ya??????????????????


Hey....What can I say ????

Even as a tyke, While other's played with their toys I had to take mine apart to see how they worked. :)


http://i107.photobucket.com/albums/m314/Restrorob/100_6141.jpg?t=1188005600?px_fullquility_384564

This pad surface was worn to the point part of the white plastic winding sleeve was exposed. I see no sign of any bonding agent on the inside of the sleeve or on the center dowel to hold it in place, It pushed out of the sleeve very easily.

The only thing I can figure is the dowel is inserted into the winding sleeve then this sleeve is some what pressed into the lining in a recessed cavity thus tightening the dowel in place ? then the lining bonded to the steel backing plate.

The center dowels in the new pads were about 3/8" or so longer which would give more mass to magnetize in return a stronger pull for better braking power.

I suppose we can put this trailer brake job/learning experience to rest now......

Thanks again everyone !!!

olyman
08-25-2007, 09:12 AM
:cool2: :cool2: :cool2:

fixer67
08-25-2007, 09:13 PM
I though that center dowel pin was suppose to be welded to the backing plate. From your picture it looks like it may have been at one time. That shinny part looks to be were the weld broke loose

Restrorob
08-25-2007, 09:59 PM
Nope, No weld in sight not even on the new ones.

That gray area inside the pad is silicone of some kind.

The shinny part is where the plastic winding sleeve was touching.

Now, There is a 3/16" thick disc bonded (not welded) to the bottom of the dowel pin. It looks like two different materials.

Most likely the dowel is a softer material to wear with the pad lining and this 3/16" disc (harder material) was supposed to be a press fit into the backing plate to keep the dowel from pulling through.

If that's the case that is what failed, The dowels on all four pads had pulled through the winding sleeve (most likely from heat/cooling over the years) reducing their size which caused less mass to magnetize so a weak pull.

fixer67
08-26-2007, 12:10 AM
OK. Now I understand. The winding was moving in and out when you applied the brakes but the pads were not going with it. No wonder you did not have any brakes.

olyman
09-02-2007, 05:44 PM
and now that your a wiz with trailer brakes------------------------going to be a mobile trailer brake mech?????????????????:) :) :) :cool2:

Restrorob
09-02-2007, 08:19 PM
Not on "YOUR" life....:nono:

I'm happy sitting on my roll around crapsman seat I built under my four bearing trolley 'I' beam system I built with a 880 lb lift winch hanging in front of my BIG shop fan working on peoples abused equipment. :)

You can see both in the back ground;


http://i107.photobucket.com/albums/m314/Restrorob/Chopper%20Transporter/100_60552.jpg


Oh, The frame hanging from the 'I' beam is the heli-porter I built. :waving:

olyman
09-03-2007, 05:58 PM
and whats a heliporter?????????????

Restrorob
09-03-2007, 07:13 PM
I just knew you couldn't stand it and have to ask !!!! :laugh:


Post #10 in the below thread is the beginning post of what a heli-porter is......:D


http://www.lawnsite.com/showthread.php?t=194569&highlight=helicopter

olyman
09-03-2007, 07:30 PM
ever get down that way--someones going to need a workout!!!!!!!!!! turkey---thought it had something to do with a helicopter--wasnt sure--and i dont follow alllll the threads---

Restrorob
09-03-2007, 07:59 PM
ever get down that way--someones going to need a workout!!!!!!!!!!


Yeah.....We'll make that workout at the local mom & pop's BBQ house.....Their ribs are BIG !!!!!


Hey, I figured it was easier to click a link up than type since I'm a two finger-er.....

olyman
09-03-2007, 10:12 PM
:cool2: :cool2: