944 S2 failed MOT on handbrake - please help.

[Goodoldmick]

Hello please can you help?
I've got a Porsche 944 S2. It's only done 70 (seventy) miles since it was last MOT tested in June 2009. I've decided to sell it because I don't use it so took it for an MOT last week. I took it to the same MOT place that passed it last time but this time it failed because of the hand brake not being efficient and also out of balance.

I took it home and adjusted the shoes through the hole in the disc until each one locked then just backed it off so the disc turned. I pulled the hand brake on one notch and tried to turn the wheels (with the wheels now fitted again). They were solid, I couldn't budge them. Back to the MOT station "" failed again, same problem!

I couldn't believe it.
At this stage I would just mention that the whole braking system was renewed just 600 miles ago so all the discs and shoes are like new, for this reason I hadn't actually removed the discs to see if any of the mechanism had seized up because after all it was locking the wheels. I now removed both discs and made sure everything was moving freely in the linkages which they were. I set everything up again and went back to the MOT station "" failed again, same problem.

It seemed that the pads just weren't gripping the discs. Ah, I know what it will be I thought, the new discs may be too smooth for the pads to grip (even though they had passed on the previous MOT test). I took the discs off once again and sure enough the contact surface was lovely and smooth and shiny. I made a good job of roughing up the surface of both the shoes and the metal surface where they meet and reassembled the whole thing. I wound the adjuster nut at the hand brake lever right to the end as I had done before, then adjusted the shoes through the hole with a screwdriver until both wheels were just free of locking up. I then took up any play at the lever end by winding down the adjuster nut, pulled the lever up to notch one and tried to turn the wheels. They were solid. I went back to the MOT station again full of confidence "" it failed again, same problem.

Can anyone please tell me if this is a know gremlin with these great cars and what I can do about it. There is something familiar to me about this story. Three months ago I took an old Volvo estate to this place and they failed it on the same thing but the front wheels. I did a very similar thing and took it apart three times to make sure the pistons were free and not binding and each time they failed it again and the imbalance was the same side as the Porsche. I ended up scrapping the car. It makes me wonder if it is their rolling road that is at fault but surely not, they can't fail everybody with faulty brakes must just be a coincidence.
Any help would be greatly appreciated as I want to get it sorted and sell the car although I will be very sad to see it go []
Best regards
Mike Nettleship
Rotherham UK

 

[944Turbo]

Claim its got a LSD and get them to take it out with the g-meter thingy - it says in the testers handbook they shouldn't put an LSD onto the rollers - an MOT man showed it to me once. Alternatively I think the cables can get sticky on one side or the other at the rear.
Tony

 

[Mike_Pollock]

Hi and Welcome, even if it is only for a short time!
It is a known weak spot, my 2.5 failed on it one year, but it sounds like you've done all the things I did, and you've got newer kit to start with!
The only thing would be to try to bed the shoes in. Find a nice quiet road and use the handbrake (gently!) just to get maximum contact area.
They should be 15% (of car weight) effective and that should be achievable.
It does seem that your tester has a particular thing about them.

 

[Goodoldmick]

Thanks for your reply, the sticky cable is a possibility but excuse my ignorence, LSD, isn't that a drug that hippies used to use, not sure what it means when refering to cars []

 

[Goodoldmick]

Thank you for your reply, actually the guy at the MOT station suggested I did what you suggest and drive it for a while with the brake on but I thought that would only polish the surface and reduce the grip even more so I did the opposite and roughed them up. Looks like I'm outnumbered on that one so will give it a try.
Cheers
Mike

 

[BlackMagic]

I had this a few months back and it was the brake cable. The inside had rusted and fused with the outside.
The cables are cheap and easy to replace.
Look especially at the brake hub end where it is in all the spray/salt from the road and you will probably find that the inner cable moves with the outer one.

 

[Goodoldmick]

Thank you BlackMagic, that's something I didn't check but will tomorrow.
Regards
Mike

 

[tref]

Every 944 I have taken to the MOT inspector (that isn't a pampered garage queen) has failed the MOT initially on the handbrake. My MOT inspector keeps telling me now that he has seen me get better performance than this or that on them... In truth, I don't do anything special, other than strip them down, wire brush off everything, and put them back together using a tiny amount of grease for bits that move, and a tiny amount of copperslip for bits that don't. That includes greasing between the sping and faces of the shoes, but when I say tiny amount, I mean barely enough to change the colour of the metal - any on the friction surfaces and you'll have a really crap handbrake. Whatever, it is all I have normally had to do to get them to pass.

I have adapted my driving style to include applying the handbrake whilst moving now and again, and am sure this helps. And this leads to the exception to the "Normally" above - I sware I must be the only person to have genuinely worn out a set of handbrake shoes rather than just have them rust out - it has taken about 80k miles though! The MOT inspector made some "allowance" for new pads not bedded in on that one.

 

[944Turbo]

ORIGINAL: Goodoldmick

Thanks for your reply, the sticky cable is a possibility but excuse my ignorence, LSD, isn't that a drug that hippies used to use, not sure what it means when refering to cars []

limited slip differential

 

[Goodoldmick]

Thank you Tref, I'm getting some good responses this is a very active and helpful forum.
Regards
Mike

 

[Goodoldmick]

Thanks for that explanation 944 Turbo
Mike

 

[Northern924]

Hi Mike, mine was due its MOT recently and having done the same as you last (rear discs, pads, shoes) and I had to make some major adjustments before it was good for the MOT.

If you changed the same.. discs, pads & shoes.. at the rear then strip down to the hub and refit the disc with the shoes as tight as possible the tighten to 2 clicks of the handbrake.
Should pass without any porblems

 

[robwright]

I had a similar problem with MOT. Most definitely the cable either at the area where it leaves the carbody or where the two cables join. After everything you have checked that is where I would be looking.

 

[VanhireBoys]

Thanks for the advice on this subject lads.. ! I have to add a set of cables to my list for the dreaded NCT. ...!

The NCT here is a real barrel of laughs especially for an older car []

 

[pauljmcnulty]

Two things to add:

If you're taking the handbrake shoes off, renew the clips. Mine weren't, and it turned in to an expensive overhaul.

The cables aren't that cheap to replace if you can't do it yourself, I seem to remember it was several hours labour. It is a common fault though so could well be the problem.

 

[Lowtimer]

Longer term, the bedding-in and occasional clean-up-on-the-move advice above is worthwhile - use light applications only, for about 10 seconds at a time, at modest speeds, in a straight line. I also suggest you try not to leave the car parked with the handbrake on if you can manage it, especially for long periods of time. Obviously this is easier in a level garage than parked on a steep street!

 

[peugeot]

+ 1 on the cables , incidently what side mostly fails ? .Bet its the passenger as this is the more difficult cable to do . Just fitted mine (passenger) last week and going for retest tomorrow night . Ill post the result[&:]

 

[Goodoldmick]

Thanks for your help everybody, I'm sure I will be able to solve the problem now.

Regards to all
Mike