Clutch Pedal - what's yours like?

MartinClan · #1 20th August 2007, 19:04

Just bled the clutch using one of those Easy Bleed thigies - seems to work quite well. But....

Having bled the clutch I find the following.

1. It seems to tarvel about an inch before there is any feel at all.
2. Then you get some resistance but the final "bite" comes when the clutch is about 2/3rds down. Can't comment on how well the clutch is disengaing 'cause I haven't got a propshaft yet!
3. Its also pretty heavy when it finally starts doing something...

Also - alarmingly - the clutch master cylinder moves rather a lot under the pressure of the pedal. At lease some of this seems to be because the top of the bulkhead is flexing - wow!

I would be interested in how the clutch on other BMW based Marlins feel. I just hope I dont have to take the pedal box out (again) to do any re-inforcing. It's gonna be a real b1tch to do now everything is in place....

Unhappy :-(

Robin

Patrick · #2 20th August 2007, 19:22

The clutch is very hard to push, it does bend all over the place - which is a bit worrying. I've got a new master cylinder, slave cylinder & clutch. Its loosed up a bit since the first time I tried driving - which was a bit bracing!

I get feel pretty much straight away, doesn't bite till further down. I'll check it better next time I drive it out the garage.

We did bleed it several times before it felt good.

Stuart · #3 20th August 2007, 19:31

My clutch pedal is very hard to push. It was a complete pain to bleed and get a full pedal but i did try a easybleed kit which didnt seem to work at all so i reverted to manual bleeding and now have a full pedal. The pedal box on my car was initially bolted to the front bulkhead only and flexed like hell i added extra bolts up through the top bulkhead to stop the flexing. Ill try find a picture for you.

MartinClan · #4 20th August 2007, 19:36

Quote:

Originally Posted by Stuart

My clutch pedal is very hard to push. It was a complete pain to bleed and get a full pedal but i did try a easybleed kit which didnt seem to work at all so i reverted to manual bleeding and now have a full pedal. The pedal box on my car was initially bolted to the front bulkhead only and flexed like hell i added extra bolts up through the top bulkhead to stop the flexing. Ill try find a picture for you.

I will try and bleed it again - manually this time (but not tonight...)
Mine is already bolted to the top of the bulkhead and it still flexes! I thiink I might bolt a strengthening piece across the top of the bulkhead and see if that helps.

Cheers

Robin

Patrick · #5 20th August 2007, 20:26

Its the thickness of metal used for the sides of the pedal box, the accelerator pedal flexes a lot too but you don't need as much force with that one.

My plan is to take it out at some point and add an extra layer of metal.

I've also been wondering if a race pedal set like the ones rally design sell may fit. Those look a lot stronger.

peterux · #6 20th August 2007, 20:37

Mine is quite firm too. It does seem to flex a bit and I get a full travel before the pedal hits the floor. I think the BMW pedal box must have had some kind of mechanical advantage and i think had a helper spring?
I manually bled it with my son on the foot pedal. ( i knew there must be some advantage of having kids!

)

My brake pedal is firm once I get about 2/3rds travel which is a bit long. I think they might need another bleeding session and i might need to fit one of those spacer thingies you guys fitted.

Peter

Simon · #7 20th August 2007, 21:36

The clutch was quite tricky to bleed on my Cabrio and took several attempts before the pedal felt right.

When converting my clutch from cable to hydraulic I copied the geometry from my 5 series donor and used the BMW helper spring assembly. The clutch pedal now has very good feel to it and is firm to begin with and then relaxes once the pedal goes beyond the 'over centre' position. The following link should show the set up:

http://www.flickr.com/photos/marlin_...rio/301183979/

Simon

MartinClan · #8 21st August 2007, 18:56

I experimented tonight with bolting a piece of box section tubing to the topside of the bulkhead where the pedal box bolts through.

It almost stops the top of the bulkhead flexing completely and reduces the movement of the clutch slave cylinder - although doesn't totally eliminate it - the pedal box itself must also be flexing. Interestingly it seemed to also improve the feel of the clutch pedal.

So I think I will bolt a piece of 30x30mm box right across the top of the bulkhead. It means some messing about with the little plates I made up to mount the BMW fuse box at the other end - but positioned correctly it will also give something positive for the scuttle closing plate to land on rather than just use the horrible self tappers that Marlin suggest.

I haven't bled the brakes yet, but hopefully it should help to reduce any problems with flexing due to the brake pedal being pushed.

Cheers

Robin

peterux · #9 21st August 2007, 21:09

Sounds interesting, Robin.
Be sure to post a picture when you have one or two,
thanks

Peter

jward · #10 22nd August 2007, 21:35

I have had similar problems with a hard clutch and also flexing of the pedal assembly.

To cure the flexing of the pedal assembly I welded up a bracket to fit between the pedals and the central part of the tunnel.. I bolted this to the top, and sides of the bulkhead. I ended up doing this twice as my first attempt was not strong enough. I will post a photo when I get my car back from Marlin.

I have a quite large bore Wilwood clutch master cylinder. I have thought about changing this for a narrower bore BMW cylinder in order to make the effort easier. Not tried this so far.

Jeremy Ward

MartinClan · #11 23rd August 2007, 07:34

Thanks Jeremy

I am going to try bracing the top of the bulkhead with a length of box section tubing. Initial experiments show an improvement but still some flexing of the pedal box. I would certainly be interested to see pictures of your bracing arrangement - especially if it can be done without taking the pedal box out (again....)

The pedal effort with the BMW slave cylinder is not too bad - just heavy compared to modern cars where everything always seems feather light. There is not a lot of travel on the pedal compared to the original BMW - I hope this doesn't cause problems with the clutch disengaging. Diifficult to tell yet as I am waiting for my propshaft!

Cheers

Robin