(T) Handbrake Weak - MOT fail

Hello all, I'm new to the forum so hello, and it'll be good to get to know you all.

I recently bought a 95 Barchetta without an MOT - I know, brave...but it's only failed on the handbrake. It's recording only 14% effort either side.

Tonight I stripped the brakes to have a look and did the following

-Re-greased the sliding pins, all nice and free now
-Took the disk off, sanded down both sides as there was a little surface rust
-Scrubbed the pads as they were a little corroded too
-Checked the NS caliper (ran out of time for OS) and the piston turns freely with a wind-back tool
-Took the arm rest off and adjusted the cable to it's tightest

This last step definitely activated the handbrake even when it was off, so there's enough adjustment in the cable, but even so, with the cable as tight as it will go, and 6-7 clicks on the handbrake, I could still turn the rear wheel with a breaker bar.

Any ideas why this would happen? The NS caliper is relatively new and still shiny - the OS is older but I'll try and get a look at that one over the weekend.

Thanks,
Stoocake

replace handbrake cables if you're at the end and you'll get it sorted

Hi Stoocake - welcome aboard!

The handbrake is a total ball-ache on the B - mine nearly failed its last MOT because of it.

As bollie69 says, cable-stretch can be a problem, but replacing the cables isn't a universal panacea for curing an inefficient handbrake.

If you search for "handbrake" on here, you'll find a whole host of attempted solutions, including upgrading the calipers/pads and disabling the rear compensator. See RightGuard's thread, for example:

https://www.fiatforum.com/barchetta/...fail-help.html

Short of those more drastic solutions, make sure that the rear disks and pads are in good nick, and not corroded/glazed, as that really hammers efficiency.

Best of luck with it!

Thank you both,

As I said, the cable has loads of adjustment left so I don't think stretch is an issue in this case. The pads and disk are clean, and they are Brembo grooved items so quality shouldn't be an issue.

I understand the rear compensators would be a problem with the hydraulic brake, but the handbrake should be purely mechanical (am I right?) so they wouldn't be a factor in its strength?

The only thing I can think of is that I need to loosen the handbrake cable completely to ensure that the handbrake is returning to it's fully off position.

If that doesn't work, will it be a case of new/rebuilt calipers? I can't think what else would affect it.

Thanks again

I've left mine alone for now, and have logged the job as something to do on a rainy weekend later in the year, so I'll be really interested to hear how you get on.

I was amazed that my handbrake passed the MOT, tbh, as subjectively it seemed pretty useless to me (it made very little impact on forward progress when yanked on hard at 30 mph - it must be nigh on impossible to do a decent handbrake turn in a B!).

However, I reckon that driving along for a few hundred yards with the handbrake pulled on gently, on my way to the MOT centre, helped to improve the effectiveness (although my rear disks are a bit worn/grooved, and the car had been laid up for 2 years, so that probably explains why that made a difference).

It does sound like like a massive weak point in the B.

Hopefully I can get efficiency up to 16%, after which it will just about pass. Do other calipers from other fiats fit directly to the B?

Not sure about other calipers - someone on here (RightGuard?) has fitted Tempra calipers OK, I believe.

PS - just found this thread, which may be helpful https://www.fiatforum.com/barchetta/...off-fit-b.html

Hello,

I took my 03 barchetta for its mot 2 weeks ago and it failed on the handbrake only producing 9%. I got a mechanic friend to look at it and he informed me that the only thing it could be was the calipers. He said that there is a worm gear that operates when the handbrake is applied and for some reason this was not happening. I purchased 2 refurbished calipers from wanapart and had them fitted. When i took it back for its retest the brake efficiency was 50%.

Good news there. I've got an MoT coming up and am trying to get everything shipshape, handbrake included - which was actually 'sorted' for the last MoT, but didn't feel any stronger after servicing. I'll be interested to see if a year of moderate use has made it less efficient.

The percentage figures people are citing seem really low. I mean 50% is better than 16 or 9, but it's still only half marks, no?

That's definitely reassuring news - I expect that's what's wrong with mine as I've just had a quick play, loosened the cable off, pulled the cam on the caliper back stamped on the pedal a few times to readjust the pistons, tightened the handbrake again and still not much grip on the pads (turning the wheel with a breaker bar)

If it needs new calipers, there are refurbed Tempra calipers on ebay at £65 a pop so might take the dive, although money is damn tight while I'm waiting on a house deposit being returned to me.

Regarding the actual figures - how do they test the handbrake? What are the brakes producing 16% of? Resistance to turning of a specific torque or something?

Ok. In a former life, I knew this well. However, from memory it starts with the weight of the car in kg plus an allowance for the driver of 140kg. The car is put on a set of rollers which spin the wheels. When the hand brake is applied, the resistance from the braked wheels applied to the rollers is recorded in kg. The weight of the car plus driver is divided by the resistance and then multiplied by 100 to give a percentage. In the days of being able to sit in your own car during the test, it was possible to cheat with a dodgy handbrake by applying the footbrake as well as the handbrake at the critical moment and hoping the tester didn't notice brake lights illuminating off the garage wall

Welcome to the forum anyway Steve

Ah, those were the days! In reality, of course, and outside of the MOT test centre, the wise B owner always leaves it in gear, even on the flat!

Mine sashayed a full 18" out of its parking space today - in a Norfolk-flat car park - before I realised that it was secured only on the handbrake. A lucky escape, that, otherwise it could have been written off in ASDA Great Yarmouth - what an ignominious demise for a cracking car that would have been.

Incidentally, as far as I know, in order to achieve an efficiency of 50% you would need to be able to lock both rear wheels against the resistance of the rollers AND have at least 50% of the weight of the car and driver over the rear axle. I can see how you could achieve this with a Porsche 911 but with a Barchetta you would have to fill the boot full of concrete (I'm sure I've read of members trying this)

Excellent idea - but in these parts it would have to be a sack of turnips!