I bought refurbished rear calipers from Simon Sinclair last year. I've taken the discs of for a clean-up & am trying to re-fit.
The caliper won't go over the pads. (same pads, few miles) I didn't expect to have to turn the piston in, but it wasn't going over. So I'm turning, & turning.... & I don't the piston is going back in at all.
Has anyone come across this before?
I suspect the calliper isn't fully expanded?
Don't understand what you mean C, ??
Quote from: Gaz mr-s on May 15, 2021, 19:25Don't understand what you mean C, ??
all the way out on its sliders.
screwing alone isn't enough, you have to press too. And what Carolyn said.
Quote from: Carolyn on May 15, 2021, 19:32Quote from: Gaz mr-s on May 15, 2021, 19:25Don't understand what you mean C, ??
all the way out on its sliders.
Misunderstanding maybe..... sliding no problem, caliper engaging over outside pad, but piston bumping into pad backplate. I could try more force onto it.
Are you holding the disc steady with a wheel nut?
Quote from: Carolyn on May 15, 2021, 19:50Are you holding the disc steady with a wheel nut?
Yep... two.
Very strange.
It's going to be something silly!
Take a break ands tart afresh tomorrow?
It's hard to know when it's not in front of you. ;D
Have you got the notch aligned with the nipple on the pad?
From my simplistic viewpoint the only "adjustment " is in the position of the piston, so if the pad / disc/ pad won't fit into the caliper the piston is too far out and needs pushing back in.
I'd better pay attention to this as I need to replace the rear pads soon, last time I did it I replaced both calipers so I never had to wind them back. Is the rotation of the piston handed to each side or are they the same?
Piston come to a stop, will not turn clockwise any more, but is sticking proud of the rubber seal by about 2mm.
Grumble...
Quote from: Mikeymead on May 15, 2021, 20:04I'd better pay attention to this as I need to replace the rear pads soon, last time I did it I replaced both calipers so I never had to wind them back. Is the rotation of the piston handed to each side or are they the same?
The same. Clockwise is in.
Just had a look in the Toyota factory manual - that is quite "agricultural" and suggests pushing the piston in with the handle of a hammer.
.....only the best from our main dealers!
Is the nipple on the back of the pad pined up?
Quote from: Carolyn on May 15, 2021, 20:11Quote from: Mikeymead on May 15, 2021, 20:04I'd better pay attention to this as I need to replace the rear pads soon, last time I did it I replaced both calipers so I never had to wind them back. Is the rotation of the piston handed to each side or are they the same?
The same. Clockwise is in.
Many thanks.
Quote from: paulj on May 15, 2021, 20:20Just had a look in the Toyota factory manual - that is quite "agricultural" and suggests pushing the piston in with the handle of a hammer.
.....only the best from our main dealers!
A hammer shaft is typically wood, wood is softer than a brake piston, a hammer shaft length gives good leverage, a hammer can be used for many things, a specialised tool for only one.
" Pushing the piston in with the handle of a hammer" suggests that a degree of force is required.
Quote from: Carolyn on May 15, 2021, 20:29Is the nipple on the back of the pad pined up?
That isn't relevant just now, which is why I didn't answer John above. The outer edge of the pad plate is solid, no 'cutout' sort of thing that the piston segment would slide into.
I tried taking a pic of it, but it wasn't worth posting.
Quote from: Gaz mr-s on May 15, 2021, 21:25Quote from: Carolyn on May 15, 2021, 20:29Is the nipple on the back of the pad pined up?
That isn't relevant just now, which is why I didn't answer John above. The outer edge of the pad plate is solid, no 'cutout' sort of thing that the piston segment would slide into.
I tried taking a pic of it, but it wasn't worth posting.
There isn't a "cut out" on the pad, there's a raised bump that slides into the recess on the piston, which is very relevant if you want your handbrake to work...
Quote from: Call the midlife! on May 15, 2021, 22:17Quote from: Gaz mr-s on May 15, 2021, 21:25Quote from: Carolyn on May 15, 2021, 20:29Is the nipple on the back of the pad pined up?
That isn't relevant just now, which is why I didn't answer John above. The outer edge of the pad plate is solid, no 'cutout' sort of thing that the piston segment would slide into.
I tried taking a pic of it, but it wasn't worth posting.
There isn't a "cut out" on the pad, there's a raised bump that slides into the recess on the piston, which is very relevant if you want your handbrake to work...
Give me some credit John....
The caliper with piston protruding is giving insufficient room to move over the pads & disc width. As it happens the piston is pretty close rotation-wise to the correct position, but the outer edge is butting on the pad plate.
Tomorrow I'm going to wind back the other piston & see how far it goes in in comparison.
:o Come on now John's only trying to help - It's frustrating when things don't go to plan, I know! Tomorrow's another day and hopefully it will be sorted. ;D
Quote from: Gaz mr-s on May 15, 2021, 20:08Piston come to a stop, will not turn clockwise any more, but is sticking proud of the rubber seal by about 2mm.
Grumble...
Have you compared it to the other caliper. Thats what I would do to see if it is in anyway abnormal between the two if its not going all the way in for clearance.
Edit: just read your last post. You are on the right track.
They should at least wind back to a flush position shouldn't they ?
I'm not doubting Gav here, I'm thinking summat maybe faulty ? It's an easy job, but this is a new part so may not be correct ?
Quote from: Gaz mr-s on May 15, 2021, 22:32Quote from: Call the midlife! on May 15, 2021, 22:17Quote from: Gaz mr-s on May 15, 2021, 21:25Quote from: Carolyn on May 15, 2021, 20:29Is the nipple on the back of the pad pined up?
That isn't relevant just now, which is why I didn't answer John above. The outer edge of the pad plate is solid, no 'cutout' sort of thing that the piston segment would slide into.
I tried taking a pic of it, but it wasn't worth posting.
There isn't a "cut out" on the pad, there's a raised bump that slides into the recess on the piston, which is very relevant if you want your handbrake to work...
Give me some credit John....
The caliper with piston protruding is giving insufficient room to move over the pads & disc width. As it happens the piston is pretty close rotation-wise to the correct position, but the outer edge is butting on the pad plate.
Tomorrow I'm going to wind back the other piston & see how far it goes in in comparison.
It's not a question of giving anyone credit, it's about filling in the gaps for anyone less experienced with the technology using the forum as a search tool.
New users finding the forum from a Google search on the handbrake might get confused by someone stating that the orientation of the pads and pistons isn't relevant.
Have you cracked the bleed nipple a touch? Might be too much pressure behind the piston?
Bleed nipples loosened....a little fluid out. Just started the other side & rain on hard.
I turned back the piston on the nearside...still turning but I gave up. The piston still sits proud of the rubber seal, not what I've seen with other calipers. The clearance for disc & pads is approx 46mm. Disc + pads measure 44mm.
The offside with the problem caliper measures less than 42mm.
Simon Sinclair is going to reply tomorrow.
Another thought, have you disconnected the handbrake cable at the calipers? Might be the inner mech not letting it go back far enough?
Quote from: Call the midlife! on May 16, 2021, 14:45Another thought, have you disconnected the handbrake cable at the calipers? Might be the inner mech not letting it go back far enough?
Yes
It's an odd one alright, particularly as you're just refitting something that was previously working fine.
Be interesting if there's a fundamental problem as I've got a pair of brand new ones from Simon waiting to go on but I've not heard of any other issues with his kit.
The manual suggests checking the discs for runout and advancing them a quarter turn each time until they're within spec, always the potential the disc isn't seated in the optimum position I suppose?
Quote from: Gaz mr-s on May 16, 2021, 14:37I turned back the piston on the nearside...still turning but I gave up. The piston still sits proud of the rubber seal, not what I've seen with other calipers. The clearance for disc & pads is approx 46mm. Disc + pads measure 44mm.
The offside with the problem caliper measures less than 42mm.
Simon Sinclair is going to reply tomorrow.
That does not "add up", frustrating for you to say the least. Remote diagnosis is always tricky but the measurements indicate that something is amiss.
Maybe the piston is too long, because it was supplied in a box from the factory doesn't always mean it's the right part.
Ask me how I know!
Quote from: paulj on May 15, 2021, 20:20Just had a look in the Toyota factory manual - that is quite "agricultural" and suggests pushing the piston in with the handle of a hammer.
.....only the best from our main dealers!
I had another go at turning the problem one, & it did! Me hearing a clunk as if it was coming to a stop yesterday must have been a red-herring...the other side still turns with 46mm disc/pad gap. Are they not supposed-to come to a stop though, then turn them in to align? I twisted two or three times yesterday & heard clunks...don't know why now.
So thinking back to Paul's post yesterday I got a wooden shaft & gave it a couple of modest hits with a wooden mallet & the damn thing moved in easily....much lighter work than all the turning!
Makes me wonder what the turning is for. Anyone got an exploded diagram showing the caliper innards?
As said, remote diagnosis is difficult, but there has been a theme here and now you've hit on it.
Quote from: Gaz mr-s on May 16, 2021, 16:06So thinking back to Paul's post yesterday I got a wooden shaft & gave it a couple of modest hits with a wooden mallet & the damn thing moved in easily....much lighter work than all the turning!
I didnt expect my post to be the useful one - perhaps they main dealers do know the right way after all!
Quote from: Gaz mr-s on May 16, 2021, 16:06Quote from: paulj on May 15, 2021, 20:20Just had a look in the Toyota factory manual - that is quite "agricultural" and suggests pushing the piston in with the handle of a hammer.
.....only the best from our main dealers!
I had another go at turning the problem one, & it did! Me hearing a clunk as if it was coming to a stop yesterday must have been a red-herring...the other side still turns with 46mm disc/pad gap. Are they not supposed-to come to a stop though, then turn them in to align? I twisted two or three times yesterday & heard clunks...don't know why now.
So thinking back to Paul's post yesterday I got a wooden shaft & gave it a couple of modest hits with a wooden mallet & the damn thing moved in easily....much lighter work than all the turning!
Makes me wonder what the turning is for. Anyone got an exploded diagram showing the caliper innards?
I'll pm you a link that might be useful.
Quote from: paulj on May 16, 2021, 17:49I didnt expect my post to be the useful one - perhaps they main dealers do know the right way after all!
;D ;D ;D ;D