MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: B_Tank88 on December 30, 2019, 18:14

Title: Handbrake
Post by: B_Tank88 on December 30, 2019, 18:14
I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?
Title: Re: Handbrake
Post by: Carolyn on December 30, 2019, 18:16
Quote from: B_Tank88 on December 30, 2019, 18:14I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?

Are you slackening it right off for the brake pedal dance?
Title: Re: Handbrake
Post by: B_Tank88 on December 30, 2019, 18:21
Quote from: Carolyn on December 30, 2019, 18:16
Quote from: B_Tank88 on December 30, 2019, 18:14I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?

Are you slackening it right off for the brake pedal dance?

Yep definitely. I'll have to adjust it again anyway so I'll make sure I do the same again.

What I did last time was I kept tightening it until it actually held a little bit when the handbrake wasn't applied, and then I slackened it until it stopped grabbing. Had to tighten and loosen few times to get the sweet spot but it held very well after I did this.

Don't know if this would have messed with the brake pedal dance though as obviously I did that before tightening it in the first place.
Title: Re: Handbrake
Post by: Carolyn on December 30, 2019, 18:28
Quote from: B_Tank88 on December 30, 2019, 18:21
Quote from: Carolyn on December 30, 2019, 18:16
Quote from: B_Tank88 on December 30, 2019, 18:14I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?

Are you slackening it right off for the brake pedal dance?

Yep definitely. I'll have to adjust it again anyway so I'll make sure I do the same again.

What I did last time was I kept tightening it until it actually held a little bit when the handbrake wasn't applied, and then I slackened it until it stopped grabbing. Had to tighten and loosen few times to get the sweet spot but it held very well after I did this.

Don't know if this would have messed with the brake pedal dance though as obviously I did that before tightening it in the first place.
The cables HAVE to be totally floppy, so that the arm on the caliper is all the way relaxed.  The final tightening should just be a simple 'six clicks'.  There should be no need for fine adjustment.

Engine on?  Twenty firm slow hard pedal presses?

Just checkin'...
Title: Re: Handbrake
Post by: B_Tank88 on December 30, 2019, 19:59
Quote from: Carolyn on December 30, 2019, 18:28
Quote from: B_Tank88 on December 30, 2019, 18:21
Quote from: Carolyn on December 30, 2019, 18:16
Quote from: B_Tank88 on December 30, 2019, 18:14I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?

Are you slackening it right off for the brake pedal dance?

Yep definitely. I'll have to adjust it again anyway so I'll make sure I do the same again.

What I did last time was I kept tightening it until it actually held a little bit when the handbrake wasn't applied, and then I slackened it until it stopped grabbing. Had to tighten and loosen few times to get the sweet spot but it held very well after I did this.

Don't know if this would have messed with the brake pedal dance though as obviously I did that before tightening it in the first place.
The cables HAVE to be totally floppy, so that the arm on the caliper is all the way relaxed.  The final tightening should just be a simple 'six clicks'.  There should be no need for fine adjustment.

Engine on?  Twenty firm slow hard pedal presses?

Just checkin'...

Yeah definitely did that, I followed that video that suggests to do that.

I'll have another go at it, I hope there is more adjustment left though as that cable is starting to stick out quite a bit through the adjustment nut.
Title: Re: Handbrake
Post by: Carolyn on December 30, 2019, 20:06
Quote from: B_Tank88 on December 30, 2019, 19:59
Quote from: Carolyn on December 30, 2019, 18:28
Quote from: B_Tank88 on December 30, 2019, 18:21
Quote from: Carolyn on December 30, 2019, 18:16
Quote from: B_Tank88 on December 30, 2019, 18:14I've adjusted my handbrake twice now in the space of 6 months or so. Each time it only seems to hold for a few months and then starts slipping and it's getting annoying now.

When I adjust it it holds very well and I do the brake pedal thing too.

Is there a lasting fix for this?

If that doesn't work, it's time to have a good look at the calipers.  Are the sliders moving easily?  If yes, you may have seized pistons in the calipers.  The calipers have to be right for the rest of the magic to work.

Are you slackening it right off for the brake pedal dance?

Yep definitely. I'll have to adjust it again anyway so I'll make sure I do the same again.

What I did last time was I kept tightening it until it actually held a little bit when the handbrake wasn't applied, and then I slackened it until it stopped grabbing. Had to tighten and loosen few times to get the sweet spot but it held very well after I did this.

Don't know if this would have messed with the brake pedal dance though as obviously I did that before tightening it in the first place.
The cables HAVE to be totally floppy, so that the arm on the caliper is all the way relaxed.  The final tightening should just be a simple 'six clicks'.  There should be no need for fine adjustment.

Engine on?  Twenty firm slow hard pedal presses?

Just checkin'...

Yeah definitely did that, I followed that video that suggests to do that.

I'll have another go at it, I hope there is more adjustment left though as that cable is starting to stick out quite a bit through the adjustment nut.
Title: Re: Handbrake
Post by: Ardent on December 30, 2019, 23:33
@B_Tank88

If you keep having to do it, might suggest yours calipers are seizing internally.
The auto adjust mech is not auto adjusting to take up the slack of the wear of the pads.
Just like mine.

As well as what has been covered  above. Are you starting with an interference fit of the pads to the disc?
Title: Re: Handbrake
Post by: B_Tank88 on January 3, 2020, 08:11
Quote from: Ardent on December 30, 2019, 23:33@B_Tank88

If you keep having to do it, might suggest yours calipers are seizing internally.
The auto adjust mech is not auto adjusting to take up the slack of the wear of the pads.
Just like mine.

As well as what has been covered  above. Are you starting with an interference fit of the pads to the disc?

I'm sorry, what do you mean by interference fit?
Title: Re: Handbrake
Post by: Bossworld on January 3, 2020, 10:14
Quote from: B_Tank88 on January  3, 2020, 08:11
Quote from: Ardent on December 30, 2019, 23:33@B_Tank88

If you keep having to do it, might suggest yours calipers are seizing internally.
The auto adjust mech is not auto adjusting to take up the slack of the wear of the pads.
Just like mine.

As well as what has been covered  above. Are you starting with an interference fit of the pads to the disc?

I'm sorry, what do you mean by interference fit?
The pads pretty much making slight contact with the discs even when the pedal isn't being (de)pressed.  Any actual 'interference' would wear off the pads within a few miles of driving, providing they're not absolutely clamped on.

The handbrake arm/cam doesn't bring the piston out much in comparison to actually using the brakes, hence the pads need to be as close as possible to the disc at rest, otherwise it'll never work to any great effect.

There's also a threaded rod (as part of the auto adjuster mechanism) of which various diagrams/GIFs exist on the internet that explain it better than I can write, as I can't remember if actuating the handbrake or the brakes brings the piston out on the threaded rod.

https://www.youtube.com/watch?v=g12uwGnKwlY
Title: Re: Handbrake
Post by: Carolyn on January 3, 2020, 10:36
Bossworld is correct on the 'interference.  You can just squeeze the caliper as tight as you can on its sliders to get the pads close to the disc.  If you can't move the sliders easily, they need attention.

The screw mechanism inside the piston is operated by using the foot-brake, as it rotates it has the effect of adjusting the piston very close to the disc, it is then pushed outward when the handbrake cable pulls on the small external lever.

To get the screw mechanism to do the adjusting, all tension must be off the operating lever on the caliper - hence making sure the cables are floppy.  You can check by hand to ensure the lever is all the way off.  The surest method is to the slacken the cables, then remove the pins that attach them to the levers on the calipers and physically push the lever all the way to its relaxed position. if it's sticky, give its pivot and spring a spray lube.

Then start the engine and pump the brakes slowly and firmly.  After that re-attach the cables and adjust up. There should be no need for fine adjustment at this point.  Just six clicks and it's firmly on.  If this does not work well, your calipers need an overhaul.  A seizing or sticky piston will move under hydraulic pressure BUT not when the handbrake (which exerts much less force) is applied.
Title: Re: Handbrake
Post by: Ardent on January 3, 2020, 18:21
@B_Tank88

expanded explanation here.
https://www.mr2roc.org/forum/index.php?msg=786930
Title: Re: Handbrake
Post by: robgee1964 on January 5, 2020, 09:13
As pointed out the caliper levers need to be pretty much fully relaxed for the self adjuster to work, off the foot brake.

On my car ive found this cannot be achieved unless you adjust the handbrake so it comes on around midway of the lever travel (i.e. takes far more than 4 clicks to come on) I know people say handbrake should come on in 3-4 clicks but really that's a utopian ideal which only works in a perfect setup. MOT is OK provided there is still a fair amount of reserve travel.

I rebuilt all the bake calipers when i got the car and have never had any self adjustment issues, when set up as described. Handbrake cables themselves need to be spot on, any friction messes things up big time as the return springs on the caliper arms then can't retract the cable, which means you end up not self adjusting correctly. The calipers need to be perfect too, as well as the arms getting gunged up, the return springs themselves go weak with age/rust etc.

There are probably quite a few cars about with less than perfect handbrake cables given they are not exactly a 5 minute job to replace.
Title: Re: Handbrake
Post by: tets on January 5, 2020, 11:35
i've got sick of mine so am going hydraulic (keeping the cables for MOT)
I appreciate fluid relaxes over time but I have to keep it in gear anyway so won't be a problem
Title: Re: Handbrake
Post by: Joesson on January 5, 2020, 13:45
Quote from: robgee1964 on January  5, 2020, 09:13..........

On my car ive found this cannot be achieved unless you adjust the handbrake so it comes on around midway of the lever travel (i.e. takes far more than 4 clicks to come on) I know people say handbrake should come on in 3-4 clicks but really that's a utopian ideal which only works in a perfect setup. MOT is OK provided there is still a fair amount of reserve travel.
..........



But, in Mr T's MR2 owner's manual, 2002 edition, page 242 :

Parking brake adjustment when pulled with the force of 196N (20 kgf, 44lbf)

5–8 clicks.   !

My understanding is that there should also  be facility to pull up the hand brake  lever further beyond the 8 click point .



Title: Re: Handbrake
Post by: Ardent on January 5, 2020, 15:39
I've counted 13 at least
Title: Re: Handbrake
Post by: Joesson on January 5, 2020, 15:48
The book says 5–8 not 5+8 (=13) !😉

Title: Re: Handbrake
Post by: Ardent on January 5, 2020, 15:51
Wouldn't that be -3
Title: Re: Handbrake
Post by: Joesson on January 5, 2020, 20:55
Quote from: Ardent on January  5, 2020, 15:51Wouldn't that be -3

Mr Jason,
The hand brake should be pulled up , not wound up!
Title: Re: Handbrake
Post by: B_Tank88 on March 10, 2020, 10:23
I need some advice..

I tried to adjust my handbrake again, this time unsuccessfully.

I followed the usual steps, slacken cable completely followed by brake pedal dance, engine on, 20 times etc.

Then tightened cable, it would not hold at all. I even tried to get it as tight as I could until the nut would start spinning the cable, but still absolutely nothing.

I did this twice, it does not hold at all.

I'm not sure what the problem is, the cables seem to be moving in the assembly, albeit one more than the other when I pull the lever.

The rear brakes are working as far as I'm aware, as I see a shiny surface to them after a drive. They rust up after a day and after a drive they are shiny.

My MOT is in 3 weeks and I need a relatively quick turnaround for this, as I don't want any downtime with the car. I will struggle to DIY this as trying to diagnose handbrake seems like a 2 person job but I won't be able to get any help for the time being so I don't want to DIY this at the moment.

I'm ok to pay a garage to sort this unless it's a very quick DIY that I can do myself.

How should I proceed?
Title: Re: Handbrake
Post by: Carolyn on March 10, 2020, 10:54
I suspect that the pistons are binding in the calipers.

The brake pedal can move them because it exerts far more pressure than the hand brake. If they are binding they will not adjust up properly either.

Time for a caliper overhaul or replacement.

There is a company that does refurbished calipers for a decent price, I believe it's called Big Red.
Title: Re: Handbrake
Post by: Gaz mr-s on March 10, 2020, 12:04
Loads of folk on the facebook group have used this company
https://caliperrefurb.com/?fbclid=IwAR1Q1m3fRi_1SY6DgnzTE8dcI9aXroZ8huwmgFCQ5Gy2UAuUPrP_ZNIylso
Title: Re: Handbrake
Post by: B_Tank88 on April 3, 2020, 14:37
Now the handbrake works! And I also passed my MOT, albeit with an advisory for rust underneath around the suspension components. Something I need to keep an eye on.

I had Tyre Medics of Hinckley do the job after ringing around a few places and have been entirely happy with the work they did. They charged me a flat cost as agreed at the start, despite the job taking about 7 hours in the end including waiting for parts etc.

We ordered 2 calipers first but after removing the old ones (after much struggling due to seized bolts) I was told they actually wound back in fine and didn't seem seized. They suggested I try the current calipers still and I agreed.

One of the handbrake cables was seized though. I suppose I should have picked this up when adjusting the cables but oh well.

So one handbrake cable was replaced, and I got new discs and pads fitted on the rear as apparently one of the discs was cracked.

The handbrake was adjusted and now finally the handbrake indeed holds very strongly with a few clicks. Let's hope it lasts!
Title: Re: Handbrake
Post by: B_Tank88 on June 1, 2021, 09:19
This handbrake on this car is driving me nuts.

It was all good and working after my last post, after one of  the cables was replaced and adjusted, and now the handbrake it's next to useless again.

I have re-tightened the cable nut near the lever already, I don't think I will be able to tighten it much more as the nut was already tightened a fair bit when I did it last.

What to try next?
Title: Re: Handbrake
Post by: Carolyn on June 1, 2021, 09:35
Please read and follow the 'How To':

https://www.mr2roc.org/forum/index.php?topic=68798.0 (https://www.mr2roc.org/forum/index.php?topic=68798.0)
Title: Re: Handbrake
Post by: Ardent on June 1, 2021, 12:45
With the handbrake off. Are the pads in contact with the disc or at least no more than 1mm gap.

Sounds like the self adjusting mech is not working
Title: Re: Handbrake
Post by: Frank Rabbets on June 2, 2021, 08:34
Trouble is one assumes the cables are free when adjusting. In the event of any adjusting problem it's time to drop the cable/caliper links and move the brake lever up and down to check they are free. Just had this problem with mine so found 1 siezed cable and 2 worn out calipers. Changed these with new discs and pads and handbrake adjusted easily, straight away and no need to touch the foot brake.