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Discussion Starter #1
Hi everyone ...
I recently posted this in a local forum here in Australia, but I in shear desperation , I thought I should cast the net a little wider hence I’m posting here too ….

I’m having a problem that is really causing me some grief …

Background
The gearbox on my son's 3ltr 75 was a mess - gears crunching, bearing noises, etc
His clutch went recently and given the condition of the box, we thought while the clutch was being fixed, we should drop the box and rebuild it too.
The average quote he got was $2000 to $2500 plus a few months wait for it to be done.
Given he has a new baby on the way and funds a little tight, as a short term solution, I offered him my spare Twin Spark gearbox until he gets around to rebuilding the 3LTR one.

while installing the TS box, we encountered 3 main issues.

1) The wheel hubs have larger bolts on the 3ltr, so I also gave him my spare Twin Spark A frame.
2) We could not use the TS clutch assembly because the donut flanges are smaller than the 3ltr ones, therefore we used the 3ltr clutch assembly to ensure it would bolt up to the lager donuts.
3) The 3ltr clutch is Pull type, so we had to change over the pivot pins where the thrust bearing fork pivots on.

It seems pretty much straight forward, a little bit of work, but it all seemed to go together ok.

Issue
1) We have everything bolted up and looking ok, except I can’t seem to bleed the clutch slave cylinder.
I tried the usual tricks, like pushing it backward, (in case there is air towards the front of the cylinder), but it still want come hard.
I’m worried, because I can’t see air coming out of the bleeder, yet the pedal goes straight to the floor and won’t come up.
I did manage to get it working at one stage, maybe 80-90% expected pedal feel, but then while trying to get the last 100%, I played with the bleeder and it went flat again.
Is there something I’m missing with this?

2) has anyone else put a TS box on a 3 litre 75?


Thanks in advance
Sam
 

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Are you using a pressure bleeder? These cars are a general pain to bleed usually, especially the rear brakes, I would err towards just sticking with it, there is most likely some air in there somewhere. Did you replace the flexible hose to the slave when doing the conversion? if not, swap that out to eliminate one source of a leak. I've found rubber brake and clutch hoses to draw in air even when there is no sign of a fluid leak

PS, I wouldn't neccessarily see this as a temporary fix, the shorter ratios in the TS box will feel nice and sporty!

good luck!
 

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dont be supprised if you son tells you to keep the 3lt box... i would, lol
 

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*****

Can you post a picture of the slave cylinder as it is installed in the car? I'm not sure about what you mean by changing pivot points.

Also when you are bleeding the clutch slave, is the bleed screw higher than the inlet hose? This is very important, the bleeder screw must be higher than the incoming fluid.


Finally these things can be hard to bleed, find a garage that a pressure driven power bleeder.

Bye
 

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Sounds like you have things right. Just keep on bleeding. Until you get some pressure you may have to push pedal down by hand and pull it up by hand. A pressure bleeder on the reservoir, or a vacuum on the slave cylinder, may be helpful.
Jes
 

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Discussion Starter #6
Hi everyone, thanks for you help.

Milanoguy....I didn't think about the position of the bleed screen.
on my car its sitting below the inlet hose.
I'll try your advice about turning the cylinder so the bleeder is above the hose.

Thanks
Sam
 

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yeah, easy mistake, gotta be a on the top, otherwise air builds up in the cylinder. on the top, it can make it out of the bleed screw.
 

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2) has anyone else put a TS box on a 3 litre 75?
I have, but didn't do it myself. It has also the 3 litre drive shafts, the flanges were taken from the original box I think.
 
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