Gear selection issue - Clutch Master Cylinder??

[jamesclarkson]

I have a 2014 S3 Sigma (5 speed) and have have an issue getting 3rd/4th gear when right up in the revs.  It will go into gear but requires some effort - it doesnt appear to crunch just doesnt smoothly drop into place, like it does when cruising along.  The gearbox was rebuilt 6 months ago and the car has done maybe 1000 miles since - however this issue has remained after the rebuild, so I assume this isnt box related now.  At the same time the clutch slave was changed.

I have read a post in the last few days suggesting increasing clutch pedal travel might help - so I will try this.  Is there anything I need to be aware of by adding additional travel - how is this set in the first place?  Can you adjust too far?  

Additionally, I think a change of master cylinder wouldn't hurt, as they are relatively cheap.  Can anyone confirm if this is the correct item? https://www.carbuildersolutions.com/uk/07-brake-and-clutch-master-cylinder-with-reservoir 

Thanks in advance, James.

[Jim 123]

Have you tried clutchless changes at different engine speeds.  If everything is nice and slick it points to the clutch.  Likewise if the issue is still evident it is likely to be in the box.

[Gsk 275]

Hi James,

Had a similar issue with my sigma recently, it was the yoke on clutch pedal. The weld had parted company with the main body/stem of pedal. 

Steve 

[DJ.]

Additionally, I think a change of master cylinder wouldn't hurt, as they are relatively cheap.  Can anyone confirm if this is the correct item? https://www.carbuildersolutions.com/uk/07-brake-and-clutch-master-cylinder-with-reservoir 

Yes that is the one I fitted to my Sigma. 0.7" bore, it was better made than the Girling one Caterham supplied.

As I said on Facebook, I had a couple of occasions where it became hard to select gears, particularly when the car was hot. I moved the pedal stop about a 1/4 of an inch and it seemed to cure it. However a few months later I headed to Scotland and had lost the clutch by the time I reached Scotch Corner. The AA couldn't fix it so I was relayed home where I took the engine out to change the slave cylinder. However, the slave looked OK and after chatting to a friendly garage owner, he suggested the master cylinder was more likely to be the culprit. In the end, I changed both and when I installed it the pedal stop could be moved about an inch further up, so I don't think it ever worked properly.

After you've checked the pedal is OK (!) I would change the master cylinder as it is very easy. The clutch should work well immediately. If it doesn't you may have to take the engine out to swap the slave and check the actual clutch plate and mechanism, but I hope you don't!

Duncan

[Garth]

Hi James - is your setup all standard? Type 9 or Mazda box (not sure when the Mazda was introduced)?

The advice I got from BGH recently (for my type 9 - but imagine it is the same for others) about whether or not the clutch was disengaging correctly was to depress the clutch fully at idle - wait a couple of seconds and then engage reverse - if there was any grating then the clutch was not fully disengaged!

I also heard for someone that it is possible to over depress a hydraulic clutch (ie push the pressure plate too far so the clutch will disengage but then re-engage a little at full pedal travel!?) - so it is important to make sure the clutch stop is adjusted correctly. Did not have to explore this further on my rebuild as clutch was disengaging fully.

Was the slave cylinder replaced when the box went back in? Everyone I have spoken to recommends putting a new one in?

If your setup is not standard then there are other things you may need to consider regarding the set up of the slave cylinder in relation to the pressure plate which I found out the hard way!

Good luck

Garth

[Tom_Arundel]

3rd gear syncro is always a weak point on type 9 boxes

[jamesclarkson]

Yes my setup is all standard - its a Mazda 5 speed box.

The slave was changed at the same time as the box was out as made sense to.

[jamesclarkson]

Thanks - I think some adjustment might help but I'll change the master cylinder as well I think.

I can make seamless changes up to about 6k rpm and after that, there is a resistance in the shifting that requires some more time (i.e. rev drop) or some additional force which I am not keen on.