Chassis Does this alko magnet need replacing?

jazzeddie1234

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May 19, 2016
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This looks worn out to me

IMG_20210503_092521.jpg


Anyone know if Trojan magnets are a suitable substitute as the description says 'suits alko'...?
 

BJM

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Stuffed I would say.Ring Couplermate they would tell you.Think they have a sale on currently.Remember Alko have l and rh magnets .Your magnet shown is an off road one has one slot.
 
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Crusty181

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This looks worn out to me

View attachment 66886

Anyone know if Trojan magnets are a suitable substitute as the description says 'suits alko'...?
That was worn out .... about 20000 km ago. Ha. Now it's completely routed. That magnet is a off-road variety because it has that slotted plastic sleeve, the plastic sleeve stops the brake actuator arm flogging out the brake magnet on corrugations. If you don't go off-road much then you can use the standard magnets. Standard magnets use retention clips and are a little easier to fit, off-road magnets you have to hold on with elastic bands when you re-assemble the drum hub.

Id stick with Alko, brakes are not really something id go bargain hunting parts for
 

Drover

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Yeah other pic looked thinner but if I was replacing the magnets I would chuck new ones on so at least I wouldn't
have to pull the damn hubs off for a good while...... they look about 2/3rds gone anyway.
 

mfexpanda

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Apr 1, 2011
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That was worn out .... about 20000 km ago. Ha. Now it's completely routed. That magnet is a off-road variety because it has that slotted plastic sleeve, the plastic sleeve stops the brake actuator arm flogging out the brake magnet on corrugations. If you don't go off-road much then you can use the standard magnets. Standard magnets use retention clips and are a little easier to fit, off-road magnets you have to hold on with elastic bands when you re-assemble the drum hub.

Id stick with Alko, brakes are not really something id go bargain hunting parts for
the 12" off road magent is $74 on ebay the full assembly is $375 on ebay
 

Crusty181

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the 12" off road magent is $74 on ebay the full assembly is $375 on ebay
The std magnets are identical spec'd to the offroad variety (aside from a plastic bush), and they are gender non-specific so can go on either side and are significantly cheaper. No immediate plans to flog the bejesus out of the van on 1000's of km of corrugations, so i went with the std. Makes replacing all 4, much less painful
 

jazzeddie1234

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New off road magnets on order - we cover lots of dirt roads.

I think I found a cause for weak brakes too. the shoes are supposed to have lubricant on the sliding surfaces (3 per shoe) plus on the magnet/lever pivot point. I reckon they have never been done since new and the arms are really stiff until I clean them up. Now the mechanism is moving smoothly. I can't believe how lazy the service people are - or do they just assume they will charge you to replace the whole backing plate every few years?
 
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Drover

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I doubt a service would be a proper clean, I give mine a spray of metho so dampen the dust then a good hit with air gun, I never lube anything just clean .... And have never seen a need to replace anything other than shoes and magnets, If serviced properly backing plate should last many years.....Big Mal is 10 yrs old no need yet.
Having another look at your pics lots of rust, I would remove all the bits, brush down, give a paint spray use some dry lube on the spindles, lots of dust in brakes so you don't won't normal grease really... I pull my hubs off at end of each autumn trip usually around 5000kms, it's a pain but van brakes seem to cop more than car drums.
 
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jazzeddie1234

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Interesting, thanks. My DMax service manual specifies all sorts of grease points on the rear shoes so I just follow that. But I will definately check them myself from now on and more frequently.

Capture brakes.PNG
 

Drover

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The trouble with van brakes is you have to pop the hub off each time you look which means you do the bearings as well, then I hook up and go for a couple of K's drive with it then check the damn things again as they should be bedded in, much prefer that to crawling under at the first stop next trip, also means I can check the brake adjustment as well, a big pain in my book thats why I usually just do it after the Autumn Sojourn, its cooler and I don't use a lot of adjectives................. I just use the metho spray to contain the dust, as its not good for you, if you use brake grease use it sparingly, you don't want any of it to get on shoes or drum/magnet surface they have a silicon grease available, the dry lube I use is just like a big crayon and have no idea where I got it from as Ive had it for 20 yrs or more and usually takes a mega search to find it.............. I will be pulling all mine off next week when I get home think new shoes will be in order as they are probably getting down and all the dirt this trip wouldn't have helped, dirt and cattle grids mucho braking......
 
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Boots in Action

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Interesting, thanks. My DMax service manual specifies all sorts of grease points on the rear shoes so I just follow that. But I will definately check them myself from now on and more frequently.

View attachment 66897
Hi @jazzeddie1234 , there is a need for some sort of high temp lubricant on all the RAISED surfaces on the backing plate. Moly grease is what I use, just a little so as not to get any on linings/shoes. The brake shoes need to slide across the raised platforms on the backing plate for proper operation. If not lubricated, the metal backing on the brake shoes eventually wears a grove into the raised o platforms and causes erratic braking as shoes get stuck in groove and cannot expand as necessary.
 

BJM

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Hi @jazzeddie1234 , there is a need for some sort of high temp lubricant on all the RAISED surfaces on the backing plate. Moly grease is what I use, just a little so as not to get any on linings/shoes. The brake shoes need to slide across the raised platforms on the backing plate for proper operation. If not lubricated, the metal backing on the brake shoes eventually wears a grove into the raised o platforms and causes erratic braking as shoes get stuck in groove and cannot expand as necessary.
I put a smear of high temp wheel brg grease on my last JOB brake backing plate wear points ,parts moved like silk.Checked again after 7000 klm trip covered in crap,dust etc so can not say whether greasing was much use at all
 

Boots in Action

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I put a smear of high temp wheel brg grease on my last JOB brake backing plate wear points ,parts moved like silk.Checked again after 7000 klm trip covered in crap,dust etc so can not say whether greasing was much use at all
Any lubricant helps in allowing the brake shoes to SLIDE smoothly across the backing plate raised surfaces @BJM . The fact that you have added some "grinding paste" as dust cannot be avoided and is still far better than dry surfaces grinding metal to metal. The raised platform surfaces provide only 3 places (for each wheel brake) to maintain shoes parallel to backing plate especially when braking and shoes are expanded/expanding. Remember too that the brake shoes are only held against the backing plate by a single spring for each shoe.
 

Drover

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I have never found a shoe to leave wear marks on a backing plate , car or trailer and the only ones seized in old wrecks laying around for years. They shouldn't really touch the plate, the tension springs along with the locator pin should hold the shoes clear. I have found a leaky oil seal helps keep rust away....dry lube on adjuster thread and maybe shoe slots and that's it...bugga all other moving parts in there....most important to keep the brake wire clear as they can easily get chewed.
 

Boots in Action

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Hi @Drover , although I have never seen wear on the brake backing plates of vans, (perhaps it is because I have not had vans long enough or not hammered them in bad conditions without checking for wear), here are some examples of backing plate wear on cars I have had experiences with. These were from cars with hydraulic drum brakes, single piston where brake maintenance was poor or non-existent! There is a definite need to reduce friction and wear between the brake shoes and the raised platforms on the backing plates. Perhaps the wear pattern is different with electric brakes???

The springs have nothing to do with keeping the shoes off the backing plate. Quite the opposite!!! They are for retraction of shoes after expansion for braking. The following is extracted from the service book for one of the vehicles:-

"Each shoe is held against the anchor by a brake shoe return spring. The shoes are held AGAINST the backing plate by a hold down spring passing through the centre of the brake shoe and fastened to a clip in the backing plate. Each brake shoe RESTS on three platforms in the backing plate. These platforms ensure parallel alignment of brake shoes to the drum. ...........".

I hope this clarifies the need for some high melting point grease on the surface areas where shoes are moving over the raised platforms even on vans.
 

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BJM

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Hi @Drover , although I have never seen wear on the brake backing plates of vans, (perhaps it is because I have not had vans long enough or not hammered them in bad conditions without checking for wear), here are some examples of backing plate wear on cars I have had experiences with. These were from cars with hydraulic drum brakes, single piston where brake maintenance was poor or non-existent! There is a definite need to reduce friction and wear between the brake shoes and the raised platforms on the backing plates. Perhaps the wear pattern is different with electric brakes???

The springs have nothing to do with keeping the shoes off the backing plate. Quite the opposite!!! They are for retraction of shoes after expansion for braking. The following is extracted from the service book for one of the vehicles:-

"Each shoe is held against the anchor by a brake shoe return spring. The shoes are held AGAINST the backing plate by a hold down spring passing through the centre of the brake shoe and fastened to a clip in the backing plate. Each brake shoe RESTS on three platforms in the backing plate. These platforms ensure parallel alignment of brake shoes to the drum. ...........".

I hope this clarifies the need for some high melting point grease on the surface areas where shoes are moving over the raised platforms even on vans.
Sure they arent the old Ford Zephyr ones from the old photo album.!