Bleeding brakes...

[jbcollier]

A couple of things can really help the handbrake operation:

- on a fresh brake job, always adjust the rear brakes with the handbrake disconnected at the wheels.  That ensures maximum handbrake travel and leverage at the wheels.

- the longer the travel at the handbrake lever, the less mechanical advantage is available.  Poke your head under the dash and look at the handbrake lever and linkage.  As the lever gets to the end of its travel, it is no longer pulling the arm straight back.  Very important to have the cable adjusted so it does most of its work in the first part of the travel.

With careful set-up, my handbrake works pretty good.

[4129R]

Rather than adjust the hand brake cable in the black hole in the tunnel, I take up slack where the cable clips on to the rear trailing arms, by cutting a small bit off large spring washers so they fit over the cable, and then packing out the metal end of the hand brake cable outer. I have used 3 spring washers on each side without the outer falling out of the housing on the trailing arm.

Much easier than 2 x  1/2" spanners down the hole, and less damage to hands etc. Dripping blood does tend to stain the cloth insets in the seats.

Alex in Norfolk. 

[jbcollier]

Good idea.  Now that my handbrake horse shoe is completely obscured by oil cooler and ac lines, I was thinking of doing the same thing.

[Steve_Lindford]

That all sounds very interesting. Alex - I read your theory on previous post - and sounds completely logical!

I will have a look under the dashboard - is there adjustment on the cable connected directly to the handle?? - or could it be that it has stretched??

I adjusted the rear brakes with handbrake not connected - and then connected handbrake cable such that the brakes don't bind. When I look in the tunnel when pulling the lever there seems to be a lot of slack to take up before it finally transfers action to the brake shoes.

Steve

[4129R]

The cable from the umbrella to the reaction lever is short and not adjustable. The cable from the reaction lever to the horseshoe in the black hole is about 24" long and adjustable by 2 x 1/2" nuts which lock together and are an absolute pig to get two. Two hands in the hole just don't fit, so you need to improvise.

If they had threaded each end of the cable outer where it ends by the drum, adjustment would have been a doddle. So I improvised the adjustment with cut spring washers. You just use big side cutters (electrician stuff) to cut about 3mm out of the spring O to make it a C, and stack them on the end of the outer, equally each side, until the slack is taken up. Simples.

Alex in Norfolk.

[EuropaTC]

I also have a problem with the handbrake ratchet which I haven't sussed out yet. I seem to have to twist the handle anti-clockwise to twist off - yet I feel it should be the other way round. It is the type without the button. It seems to have problems staying up - and tricky to push right down also...

That sounds right Steve, mine is pull towards you and twist to release.

Controversial now, but I think the handbrake as designed is poor.  You can get the 25% pass mark for the UK MoT but it takes care.  In support of that statement if you look back through period road tests you'll see they also found poor handbrakes when new.  Autocar quoted the S2 as "ok for parking on level ground, wouldn't hold on a 1:6 slope and very little use as an emergency brake".  By the time the TCS had arrived Motor said "the handbrake is still rather pathetic, very poor".

So if Lotus sent out road test cars with poor handbrakes, you're allowed to struggle !

However there are ways forward. I think it was Richard on the  Yahoo group who re-drilled the backplate to rotate it a few degrees. This means the actuating lever isn't bent to clear the trailing arm and he reckoned the revised operating arc made a big difference. That sounds a good idea if you look at the operating arc but by the time I'd picked up the comment I'd moved on. (I might be wrong on attributing it Richard, but the method I remember)

Mine has never actually failed on the handbrake but it has caused "comment" and knowing looks. Things improved slightly with a new rear cable with modified rear shoes to alter the point at which the backplate lever started to engage but then I gave in and fitted dual circuit brakes because a side benefit is that the pass mark is lower (18% ?).   But actually getting it to stop the car before you get bored,  you need rear discs.....     

Brian

[Steve_Lindford]

I did waste a bit of time trying to undo the nuts in the tunnel with a spanner on the end of mole grips - before I realised they were finger tight anyway! I will have a think about making some 'C' spacers - but I feel if anything they are needed at the front. Someone has added an additional tensioner in the tunnel which can be turned by hand - I will photograph when I get a moment.

Talking hypothetically - if the handbrake system used rods instead of cables - if you moved the handbrake 1mm - you would get a reaction at the other end. The way mine seems to be set up is that it is adjusted so it is correct at the brake shoe end - so you would expect the handle end to be automatically correct - but there seems to be too much slack there.

I cant quite picture why rotating the back plate would make a difference - but I am not disputing it.

Will have another look today...

Steve

[4129R]

With the reaction lever giving a mechanical advantage of in the region of 6:1 or even 10:1, any adjustment between the umbrella handle and the reaction lever would have very little effect on the stretching on the cable between the lever and the horseshoe.

I think that the stretching is mostly on the very long U cable from the drum to the horseshoe to the drum, and this can only be taken up on the cable from the lever to the horseshoe, or the very long U cable.

Lotus in their wisdom thought we could get our hands into the tunnel to adjust the cable. Any adjustment there would be half the adjustment to the long U cable, but as I have found, any adjustment at the drum end of the cable is simplicity itself. We should ask Richard at Banks to get a 3/8" UNF thread cut in each cable end to take a pair of about 9/16" nuts.

Alex in Norfolk, far closer to Hethel than Banks in Preston.

[Roger]

You want less movement at the brakes; that's what gives you mechanical advantage.
I suggest you take the clevis pins out of the rear brake levers, one at a time, and ask someone to operate the handbrake. You will soon see if you have free movement throughout.
Sounds to me as though your bowden cables are partly seized.

[Steve_Lindford]

This is a picture of the adjuster in the tunnel - which can be adjusted with one hand. The handbrake seems as good as it can be at the moment - but I haven't tried driving the car or moving it to a slope. I made the stupid mistake of thinking that I had to pull the hand brake - then twist to hold it in place when on - so maybe I don't have a problem with the ratchet...

Surely mechanical advantage is no use if when the handle is pulled to the maximum - the brake doesn't work??

[EuropaTC]

Hi Steve,

That's not the normal adjuster, or at least not like the OEM one on my car although I'm sure it will work. That's the sort of thing I've seen for when your cable is too long for the application and you need to shorten the overall length to get the lever arm movements back within range. I've not explained that very well I know, but perhaps someone else will be along with a better one.

The tunnel adjuster on mine is like the image. I think you'd get more effective adjustment than the one you've shown.

[blasterdad]

 
That looks like a DPO part, (Looks new) also looks like a good way to wear a hole in the coolant pipe...
Mine has the "horseshoe" as in Brian's pic.

[BDA]

I agree with Brian and blaster. That is not the adjuster for a TC. I think the stock horseshoe provides a greater range of adjustment.

[4129R]

On one of the cars I bought, the cable from the lever to the horseshoe adjuster was tied in a simple knot to shorten it !

I believe the handbrake does not work properly purely because the total cable and leverage system just does not move the lever opening the shoes apart enough to provide sufficient friction on the drum to stop the back end.

Quite honestly, I cannot understand how 1 side only of a moving brake shoe can ever stop a brake drum efficiently. Surely it needs two hydraulic pushers to make the shoe push on the drum sufficiently to work properly.

I will look at the back lever with increased concentration to see if improvements can be made on the hand brake mechanism, simply. Same movement at umbrella required for more movement at the shoes.........

[jbcollier]

The wheel cylinder "floats" in the backing plate so it works on both shoes.

John