Knobbly bits on back of pads

[moca2cv]

Bear with me here... So whilst losing copious amounts of sleep over why my brakes just don't seem to be doing the biz (squishy pedal - stopping power there, just feels rubbish) after changing pads and discs and bleeding the system, I have:
- bled more
- changed calipers all round
- fitted braided hoses
- changed the MC
- bled some more

It's still squishy. Yay. So last night I did a lot of googling about pedal feel with yellowstuffs, and lots of people have lots of different things to say, but one stuck in my mind in particular as the pads were just wrong and didn't quite work with the brakes on this particular car. So then I get to rewinding all I've done on the car and I am 99.9% sure the rear pads do not have the knobbly bits on the back that slot in to the piston.

Now I didn't think anything of it at the time, handbrake is rubbish but as it's a track car I've not really worried too much about that, but reading up on it those knobbly bits seem quite important for the operation of the handbrake self adjust mechanism. But would they give a squishy pedal? If the handbrake isn't self adjusting does this hold the pistons further back than they should be, resulting in that vague feeling?

Any thoughts appreciated, this is driving me potty!

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[1979scotte]

Always found my handbrake was rubbish when I had yellow stuff.

[Bossworld]

I've owned several other cars with a similar handbrake design to the MR2.

The rest of them hold with ease, and none of them have the rear dimples. From what I understand it acts as an anti rotation point to enable the internal adjustment mechanism to wind out, but we end up in MR2 world with all these weird and wonderful routines of having to wind out half a turn/ensuring alignment.

How worn down are the pads? If they were newly fitted then by having a near-interference fit anyway, I don't think it'd account for any spongy feeling

[Ardent]

As above. Part of the whole self adjusting  mechanism.

Pads should be interference fit.

I have a sim thread. Stock pads. Brakes work. But would like a firmer pedal at the top.

My thread initial brake feel or something.
Some good points in there.
https://www.mr2roc.org/forum/index.php?topic=71434.0

[moca2cv]

Always found my handbrake was rubbish when I had yellow stuff.

Perhaps the knobbly bits are to blame then!

[moca2cv]

I've owned several other cars with a similar handbrake design to the MR2.

The rest of them hold with ease, and none of them have the rear dimples. From what I understand it acts as an anti rotation point to enable the internal adjustment mechanism to wind out, but we end up in MR2 world with all these weird and wonderful routines of having to wind out half a turn/ensuring alignment.

How worn down are the pads? If they were newly fitted then by having a near-interference fit anyway, I don't think it'd account for any spongy feeling

They've done two track days, not new but not worn either. They've been consistently soft since fitting, throughout a bedding in process (at Brands 😁) and also at Llandow where the brakes got hammered by better drivers than me. Haven't changed a bit 😂

[moca2cv]

As above. Part of the whole self adjusting  mechanism.

Pads should be interference fit.

I have a sim thread. Stock pads. Brakes work. But would like a firmer pedal at the top.

My thread initial brake feel or something.
Some good points in there.
https://www.mr2roc.org/forum/index.php?topic=71434.0

Thanks! Will have a read. I want to believe it's air, they felt fine before I swapped discs and pads, I've got more stopping power but terrible pedal feel, but maybe it is just the pads are duffers. I wonder if I can get some better pads before Thursday...

[Ardent]

cannot recall the post now, but recently someone put a post up about yellows. They looked like they had melted.

Dodgy batch?

Search ebc yellow bound to find it. Looked like they were made of toffee.

[Ardent]

Always found my handbrake was rubbish when I had yellow stuff.

Perhaps the knobbly bits are to blame then!

As in. Lack of.

[moca2cv]

cannot recall the post now, but recently someone put a post up about yellows. They looked like they had melted.

Dodgy batch?

Search ebc yellow bound to find it. Looked like they were made of toffee.

I do recall that now you mention it. Mine don't look too bad, the paint bubbles badly but that doesn't stop you so not too fussed. There does seem to be a lot of variation in experience though, maybe their QC isn't all that?

[Gaz mr-s]

cannot recall the post now, but recently someone put a post up about yellows. They looked like they had melted.

Dodgy batch?

Search ebc yellow bound to find it. Looked like they were made of toffee.

The guys with brake knowledge said they'd been abused....allowed to get too hot.

[moca2cv]

cannot recall the post now, but recently someone put a post up about yellows. They looked like they had melted.

Dodgy batch?

Search ebc yellow bound to find it. Looked like they were made of toffee.

The guys with brake knowledge said they'd been abused....allowed to get too hot.

Top effort 😁

[Frank Rabbets]

Moca, in answer to your question the dimples should fit inside the recesses of the piston. If not, in my opinion, you could have a squishy pedal as the bad plate might be distorting under pressure before biting the disc fully.
Also try bleeding with the engine running so the brake servo gives a bit of a squirt.
I bet it'e those dimples though.

[moca2cv]

Moca, in answer to your question the dimples should fit inside the recesses of the piston. If not, in my opinion, you could have a squishy pedal as the bad plate might be distorting under pressure before biting the disc fully.
Also try bleeding with the engine running so the brake servo gives a bit of a squirt.
I bet it'e those dimples though.

Thanks Frank, the pads have no dimples though, so was wondering if that would affect anything other than the handbrake...
I've been on Spyderchat though and a chap mentioned that you could cycle the ABS with Techstream, so that's my next thing to do

[Ardent]

Might be worth replacing the pads with those with the pins/lugs/nipples first.

[Mr2paul]

Iv not heared any good things about yellow stuff. Apex brake really well and handbrake is perfect so I'd ditch those tbh and start again

[1979scotte]

Iv not heared any good things about yellow stuff. Apex brake really well and handbrake is perfect so I'd ditch those tbh and start again

I always liked yellow stuff on the road. Just parking that was the issue.
And that's on a turbo 1zz and a V6 so not exactly slow.

[moca2cv]

Iv not heared any good things about yellow stuff. Apex brake really well and handbrake is perfect so I'd ditch those tbh and start again

They've been nice and consistent on the last two track days, so can't really complain too much! Another couple and they'll be ready to swap out, I've had old Yellows crumble so it's not a good idea in my books to leave them in too long.
I really don't believe my issue is down to the pads. I'll hopefully have Techstream up and running on the weekend to test the ABS, but I do have some random pads in the garage to swap in so will do some testing when I get a chance.
In the meantime, track evening tomorrow 😁