Rear handbrake behaviour - number of clicks when foot brake applied

[bill888]

A year ago, I fitted new rear calipers supplied by Brakes international (Bremtech boxed).

Earlier today, I had to use the handbrake on a slight slope when I came to a stop at a set of lights.  As I pulled the lever upwards, I counted 4 clicks as the cable got tighter, then suddenly it felt like the cable became looser and I was able to pull the lever up a few more clicks.   (The car started to roll backwards with 4 clicks when I took my foot off the brake pedal)

When I got home, I checked the handbrake behaviour while car was stationary.   With foot firmly on brake pedal, while engine was running I could pull the lever up 4 clicks.  When I took my foot off the pedal the lever could be pulled further to 7 clicks as the cable tension seemed lower. 

With foot off brake pedal, I could smoothly pull the lever up to 7 or 8 clicks which is how it was set up a year ago.

There seems to be an issue when both the foot brake and handbrake are operated simultaneously when car is stationary.

Anyone have any thoughts about what the problem may be?
I suspect some sort of caliper issue?

Thanks in advance.


Update:   Took car out for a quick run.  I observed several times when I came to a halt and kept foot on brake pedal. When I applied the handbrake, it offered up a lot of resistance up to 4 clicks. But if I tugged the lever a bit more, it overcame the resistance and the tension seems to drop a bit, allowing the lever to  advance to 7 clicks.

While foot brake still applied, if I then subsequently release the handbrake and apply it again, it was a bit smoother (less notchy around the 4th click?) and advances to 7 clicks.   Release the handbrake again and reapply, and the lever operation is smooth.

If I don't touch the foot brake, the lever pulls up to 7 clicks in smooth action, ,so I don't think there is a problem with the handbrake cable.

Very weird.

hmm, looks like I may have to consider buying another set of rear calipers to try and identify which caliper may be partially faulty.

When I have spare time, I'll remove the centre console and observe the cable movement when handbrake is applied. It may give a clue which caliper is faulty.

[madasafish]

Seems normal.
When footbrake on, the pad extends to touch disk.But brake balancing valve stops hard braking at rear so pad movement limited. So hand brake when applied and footbrake released has more distance to make up - the movement of pad to disk when footbrake on - hence more clicks needed. No limit on pad movement as cable operated not hydraulic.

[bill888]

Thanks for your interesting comments.  I conducted a few more tests this morning.

With firm pressure on brake pedal, I perhaps should have started with the handbrake is much MORE difficult to lift.  Once the lever reaches half way when it becomes extremely difficult to lift it any further, there's a 'thud' and the tension drops to allow the lever to advance further.  The thud happens even when the handbrake button is pushed in (ie. not noise from ratchet mechanism)

Without applying brake pedal, the handbrake is much easier/smoother to lift to maximum lock position.  ie. normal.

At the moment, I can't think of a way of isolating a caliper to help determine which one may be causing the problem.  I think I'll have to contact Brakes Int. to see if they have any suggestions and how their 2 year exchange warranty works.

[madasafish]

Look at the condition of the rear disks though the wheels.

Both disks shiny to the outer edge? OK.
One disk not shiny to outer edge? Fault somewhere.

[bill888]

Just checked.  Yes, discs seem to look fine to me looking through the wheel spokes. Look no different to the front brakes I did two years ago .  ie. Shiny discs all round.  No lip or raised rust on outer edge of the painted Pagid discs.

This car isn't used much, under 1,000 miles since all new Pagid discs, Brembo pads and Bremtech calipers fitted 11 months ago to the rear.  (Total mileage not yet reached 19k. Passed MoT last October)

It's a CVT auto, so the handbrake doesn't get much use.  I do know handbrake was behaving normally a month ago as I use handbrake to hold car at traffic lights on slopes around here.  It's just last few days I've noticed something is not right when car started to roll...

I'll try jacking up each rear corner to spin the wheel and double check the foot brake is working later this week.

Emailed fired off to Brakes Int.  I note on ebay rear caliipers cost as little as £35 each with 5 year warranty thrown in?!

[embee]

Not sure if the your Jazz is the same, but the "normal" routine for resetting rear calipers is to loosen the handbrake cables completely so the self-adjusting mechanism in the caliper is backed right off. Then apply the footbrake (service brake) a good few times to get the caliper pistons to move to their normal operating position, then adjust the cables until there is just minimal free-play. This "should" give something like 5-7 clicks typically (model dependent) of handbrake travel.

I don't know if you've done this previously. Might be worth a re-try.

If you don't go through this it is possible for the caliper handbrake mechanism on one or both sides to reach the end stop  before the pads fully grip the disc. I had exactly this issue on a car I had from new once, went in for its first MOT and failed on one side with no handbrake, found the cables were adjusted completely incorrectly (either in factory or dealership). Reset and all operated perfectly.

[bill888]

Handbrake was adjusted correctly by slacking off cable tension, applying brake pedal many times etc.  when I installed the new parts under a year ago.  (Passed MoT last October fwiw)

I can certainly try resetting handbrake adjustment to see if it makes any difference.  Brake fluid change also due.

Fwiw, I found my old posts.
Rear brake calipers and discs, 2022:
https://clubjazz.org/forum/index.php?topic=14584.msg119118#msg119118

Front brake calipers and discs, 2021:
https://clubjazz.org/forum/index.php?topic=12753.msg93381#msg93381

[Henryge]

Hi There, Check the cable wire where it is exposed that is by cailpers and also hand brake end attachment.
              The wire cable may have frayed at those points causing it to catch hard and when more leverage is                                                                       
              applied then pushes through.     

[bill888]

Handbrake works and feels absolutely fine as long as  I don't use the brake pedal.  Pressing the brake pedal shouldn't make the handbrake more difficult to operate, but it does - it's very bizarre.

Weather permitting, I'll take the wheels off and have a closer look at the cables, calipers and try resetting the handbrake next weekend. 

Thanks to all for all the suggestions so far.

[Lord Voltermore]

It may pay to check that any moving parts are free to move freely, and lubricated (where appropriate)  in the correct manner with the correct lubricant.      Cable handbrakes typically have self adjustment mechanisms  with hinged metal plates, cam adjusters  etc  which  can click round automatically to compensate as brake linings wear down.
These moving parts can rust or get jammed with brake dust etc causing unbalanced  or sudden large changes in adjustment.        Its also possible these parts  have suffered mechanical wear, cables stretched etc  and need replacement but this is less easy to diagnose. Professional mechanics may prefer to replace them with new parts  as a matter of routine rather than spend time,cleaning ,lubricating etc, with no guarantee of a fix. 

[bill888]

I've looking at cost of new cables (£50) and calipers (£70). I agree it is easier to just swap out the parts to fix issue by trial & error method.

Following madasafish's line of thought, it's possible the piston in perhaps one of the 11 months old rear calipers is 'partially sticking' only when pedal is depressed in some unknown manner.  Subsequently, when I come to operate the handbrake lever while pedal is depressed, I'm having to apply more than necessary effort to overcome the partial seizure.

Everything is speculation at this moment in time until I can get time to take wheels off and inspect the brakes in next fortnight.

[bill888]

Serviced the car during the weekend, oil, plugs, CVT fluid.

While changing the brake fluid, I noticed the rear offside brakes were creaking while handbrake was fully applied while I was jacking up or lowering the car.

I checked the handbrake cable adjustment this morning.  Prior to adjustment, with handbrake in 1st notch position, the nearside rear wheel starts to drag.  I had to raise the lever to 5 notches before the offside rear wheel started to drag.

I slackened off the handbrake cable tensioner, pumped the brake pedal several times, and tightened the nut.  Both wheels start to drag at 1st notch handbrake position.

Looks like there is an issue with the offside caliper.

In hindsight, it may be related to the issue I observed a year ago where with handbrake released, the CAM on handbrake mechanism was not resting against the STOP and there is tension on the cable.  (If the tensioner is loosened, the cam does rest against the stop)

Best guess is the handbrake self adjustment mechanism isn't working on the offside rear brake caliper.

I will update once I hear back from Brakes International.

[Jocko]

It looks like the cam is seized. Needs cleaned and lubricated.

[altom2]

I had both rear brake calipers replaced in January of this year - one caliper then the other a week later as the problem hadn't been sorted. Within a short period the handbrake felt 'slack' and required pulling up to 10 clicks or more - I assumed that the handbrake hadn't been adjusted properly. After much indecision (did I want to take it back to a garage that had twice sent me out with dodgy brakes?), I took it to another garage, where I was informed that both calipers were 'knackered' and would not pass the MOT. The mechanic showed me that, when the handbrake was applied, the cams were moving sideways. The readings on the testing equipment were about half of what they should have been. Also, one of the calipers was sticking. The calipers were replaced under warranty - fingers crossed.

[Lord Voltermore]

The photo illustrates well why professionals  sometimes prefer to replace such parts rather than spend time cleaning and lubricating.  If protective alloy plating has corroded  cleaning it off  may leave the part  vulnerable to more rapid deterioration  . Moving parts may already have suffered excess wear.  And lubrication would need to be the right stuff in the right place in the right quantity .And might still attract abrasive dirt.  May be worthwhile if you can do the work yourself  (and again if and when it needs it)  but garages may be reluctant to  guarantee the work.