Hydraulic brakes

[noelm]

Just in the process of doing some maintenance on my trailer suspension before the frame comes back from the galvanisers, it's got ARK hydraulic caliper with stainless pistons, the brake pads are shot (as usual) but after pulling it to bits, I can't see anything to hold the pads in, no idea if there was something that's rusted off or fallen off, anyone know? Surely they don't just sit there? They have two holes in the pads, but no matching holes in the caliper, there must be some kind of clip? Google doesn't reveal anything either.

Edited December 20, 2022 by noelm

[frankS]

Don't know if this is any help or not

Frank

[noelm]

That's the one, but, there's nothing to hold the pad in, surely it doesn't just sit there, the calipers are mounted on their side, not vertical with the pad sitting in by gravity. There is a little sort of groove as you can see in that picture, and those little tabs on the pad just sit in that, but, nothing stops it just coming out.

Edited December 21, 2022 by noelm

[noelm]

I have the calipers off and thinking of removing the piston to make sure it's OK, but they are stainless and still like shiny, and the rubber boots are fine too, it's just the pads that have me puzzled.

[Bryant fish]

They just sit there the rotor stops them from falling out

[noelm]

How can the rotor stop them falling out? They come out from the top, you don't need to loosen bolts or anything to change them, they were all the same, pads just sitting there, no clips or anything.

[Smobaby]

There should be a small slot in the centre of the calliper that allows the pad to slip into position then move to the side .The pads are not able to just  slip in they are larger than the gap in the calliper . Have a close look at the picture in above post there is a slight rebate at the to of the pad which slots into the retainer on the calliper. 

[zmk1962]

They slot into place (at least they did on my Trigg brakes). When you assemble the brake, the pads slot into that groove. There is a slot cut out to put them in and slide them to each side. Once the caliper is in its normal position the rotor sits between the pads and prevents them sliding to the slot. 

Cheers Zoran
 

[noelm]

If you look at the picture Frank posted, they are my calipers, there is a groove kind of thing going across the caliper, the lugs on the pad, just sits in the groove, you can pull the pad straight up, there is/was nothing to retain it! I have seen the one you posted, and almost every car caliper, but this is a puzzle, I am going to examine it closely soon, I have them off, sitting in the bench.

[noelm]

I think I might be on to something, the tab on the pad has a very slight triangle shape, and the caliper has a similar shape in the groove, the pad slides in an open bit, then across and it catches on the triangle bit.......I think.

Edited December 21, 2022 by noelm

[noelm]

Yep, that's it, can't believe I didn't see it before, once the triangle bit is slid along that groove, it can't come up, I think  my brain was just frizzled from pulling the springs and stuff off........pretty tricky on your own!

[noelm]

The only hot/warm day for weeks and I pulled my suspension to bits...in the sun...out of the wind!  I have changed the pads before, but thought I must have been having a "senior moment" or something, they are similar to my Prado, except the Prado has two pins with a spring clip to retain the pads. I think because they were actually off the trailer, (rather than sticking my head under the guard)  they just looked wrong.

[noelm]

Has anyone pulled the piston out of the caliper before? I can't imagine it would be that difficult.

[Bryant fish]

There is no reason to remove piston if you muck around with it you may have to bleed the system just use a g clamp or similar to push it in

[noelm]

I have to bleed it anyway, it's all in pieces, I was just dreaming about doing it while it's all off the trailer.

[XD351]

Don’t take the pistons out , if they are not rusted and moving easily they will be fine . There is the risk of it leaking after reassembly and if you get even the tiniest bit of dirt in there you will end up with a piston sticking - I doubt you can buy a rebuild kit anyway so if it is stuffed replace the whole unit .

[noelm]

They are/were working OK, which is surprising really, it was just a "thing" I thought of.

[back cruncher]

Hi all…Noelm,I just done my brakes.the piston has a groove with an o ring.my brakes are deemax,and I bought a rebuild kit,it came with the o ring.

[noelm]

I can't imagine they would be difficult, but as they say.....if it's not broken...don't fix it! Got my trailer back today from the galvanisers, turned out pretty good, ended up being $1,800, all up, that's all the brackets and guide ring and the frame. Still a bit dearer than $7 per KG @220kg, but the guy said they charge more for small bits and pieces, anyway, I will start putting it together tomorrow once I get the suspension sorted, will take a few pictures tomorrow as well.