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Upside down slave cylinder and 9.5mm throw


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Hi Les.

Thanks for the measurement of 25mm, but I do not know how you got that result, it is only possible to get that measurement with the rubber dust boot removed, which you say you have yet to remove, pick a datum point with a tape measure and then very nicely ask the wife to depress the clutch pedal the difference will be the rough M/C push rod travel, when I corrected the problems you don’t have I got 30mm.

I will wait for your next measurement and hopefully it will be nearer 30mm or above.

As you know unfortunately no one ever gave me that distance, possibly because no one wanted to remove the dust boot, a bitch to refit. 

All the best.

Mick

 

 

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MJF

Good to read your reply.

What you wrote would be very helpful to Les, as others have said check you have the correct pushrod, especially with all Les’s S&M problems.

Mick.

MJF

I should have also added your sentence (Sorry for any confusion, I think the lengths I quoted are for the effective length of the pushrod, this is the distance between the centre line of the clevis pin holes and the end of the operating arm, as this is the length which determines clutch operation) is, as you know in engineering terms 100% accurate, mine was just basically the length of a piece of metal.

Mick. 

Edited by mhossack
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Hi All,

Cracked it. When I looked again I found the clutch pedal was lower than the brake pedal. As soon as I removed the clevis pin the pedal shot forward. That is where the extra movement will come. Removed the push rod and it is just 75mm long. When it is this short it restricts how far the pedal can come up and thus the overall movement.

I am convinced a longer push rod will give me all the throw I need. So, so pleased with this result. Thank you to all of you.

Looks like Martin and I had very similar measurements.

Last two questions. Where can I get the correct length push rod? And how on earth do you get the rubber boot in place. I don't think mine has ever been properly seated in 43 years.

Thanks again

Les

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1 hour ago, Les Pettitt said:

And how on earth do you get the rubber boot in place. I don't think mine has ever been properly seated in 43 years.

Get the boot nice and warm with a hairdryer or hot air gun, put plenty of lubricant (silicone grease or petroleum jelly) on the mating parts of the boot and ease it in from the front towards the back. You might need a little bit of gentle prodding with the flat blade of a screwdriver to correctly locate the last bit of the lip. It is actually quite easy if you take your time.

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Les,

I got mine from TR Enterprises a couple of years ago. I think they had a batch re-manufactured as at the time originals were no longer available from the usual suppliers.

Martin

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Hi Red6

Many thanks for that advice, that is the first time I have ever seen it mentioned.

Hi Martin,

I know Moss don't stock it but it appears Rimmers now do. I have asked them for the length of their 122296. I hadn't thought of TR Enterprises, I'll contact them.

Many thanks

Les

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2 hours ago, Les Pettitt said:

Hi Red6

Many thanks for that advice, that is the first time I have ever seen it mentioned.

Hi Martin,

I know Moss don't stock it but it appears Rimmers now do. I have asked them for the length of their 122296. I hadn't thought of TR Enterprises, I'll contact them.

Many thanks

Les

Hi Les

I have 122296 from Rimmers I'll hunt it out tomorrow and measure it for you from the clevis pin hole centre to the end.

Andy

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16 hours ago, PodOne said:

Hi Les

I have 122296 from Rimmers I'll hunt it out tomorrow and measure it for you from the clevis pin hole centre to the end.

Andy

The length is 82mm with the threaded portion of the rod flush to the rear slot in the clevis pin if that makes sense. So at its minimal length without the thread entering the clevis slot.

Andy 

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Hi Andy,

That is brilliant thank you, I'll get one from Rimmers.

In hindsight, I tackled this problem from completely the wrong direction. I should have measured the throw of the master cylinder push rod first. With my 0.7" master cylinder and 1" slave giving a throw ratio between master / slave of approx 2:1,   I would then have realised I would need at least 30mm throw at the master cylinder so my 25mm throw at the master would never give me enough throw at the slave cylinder whatever I did to it. Moving from a 75mm master push rod to an 82mm one gives me an extra 7mm which when added to my existing 25mm gives me 32mm, perfect for a slave throw of 16mm if I bleed thoroughly. Even If I had done things this way round I don't think I would have realised the master push rod was too short so thanks everyone for pointing this out. I can also now see that if I used an even longer (adjustable?) master cylinder push rod I would get even more throw but the clutch pedal may then be unacceptably high. I wonder how many others are suffering a poor clutch because of a short master cylinder push rod. I am surprised our retailers aren't aware of the potential problem or maybe they are now as my master cylinder would have been fitted three years ago.

My final request on this topic is whether anyone can explain why the master cylinder piston doesn't drop out of the bore when I remove the push rod. I don't need to remove the piston right now but I am thinking about some time in the future when I may have to replace the seal. How do you get the piston out?

Thank you all again.

Regards

Les

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21 minutes ago, Les Pettitt said:

In hindsight, I tackled this problem from completely the wrong direction. I should have measured the throw of the master cylinder push rod first.

My final request on this topic is whether anyone can explain why the master cylinder piston doesn't drop out of the bore when I remove the push rod. I don't need to remove the piston right now but I am thinking about some time in the future when I may have to replace the seal. How do you get the piston out?

Thank you all again.

Regards

Les

I did say way back that it was master cylinder pushrod length.

There is a circlip to hold the piston and the pushrod in the bore.in the bore.

Stuart.

 

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52 minutes ago, stuart said:

I did say way back that it was master cylinder pushrod length.

There is a circlip to hold the piston and the pushrod in the bore.in the bore.

Stuart.

 

And as I said no need for a adjustable one hope it works Les

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Hi Les/Stuart

Even with the circlip out mine stayed in the bore even with the crud removed from the top of the bore I had to keep pushing the piston down the bore against the spring and releasing it until it popped free, perhaps a weak spring or it maybe a normal? I've not stripped enough of them to comment further and rebuilt it using the old spring. The spring for the 0.7" I couldn't find a supplier but the 0.75" is listed by Rimmers.

Anyone know a source for the 0.7" spring for future reference?

Andy 

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Just now, PodOne said:

Hi Les/Stuart

Even with the circlip out mine stayed in the bore even with the crud removed from the top of the bore I had to keep pushing the piston down the bore against the spring and releasing it until it popped free, perhaps a weak spring or it maybe a normal? I've not stripped enough of them to comment further and rebuilt it using the old spring. The spring for the 0.7" I couldn't find a supplier but the 0.75" is listed by Rimmers.

Anyone know a source for the 0.7" spring for future reference?

Andy 

You do quite often have to bang them hard down on the bench with the end of the cylinder down to dislodge them when theyre heavily crudded up but TBH if theyre that bad then you`ll more than likely find theyre knackered anyway.

Stuart.

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7 minutes ago, stuart said:

You do quite often have to bang them hard down on the bench with the end of the cylinder down to dislodge them when theyre heavily crudded up but TBH if theyre that bad then you`ll more than likely find theyre knackered anyway.

Stuart.

Rebuilt mine a few years ago and is sat on a shelf since so just to reassure myself I'll re-strip it and check the bore. Out of interest Stuart which supplier would do you use for replacements or is it worth getting Past Parts to re-sleeve/recondition the original Girling? 

Andy

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Just now, PodOne said:

Rebuilt mine a few years ago and is sat on a shelf since so just to reassure myself I'll re-strip it and check the bore. Out of interest Stuart which supplier would do you use for replacements or is it worth getting Past Parts to re-sleeve/recondition the original Girling? 

Andy

Ive been happy enough with TR Shop supplied stuff but do keep original push rods ;) I have someone down here who re-sleeves them if required. Ive no experience of Past Parts more than supplies of seals.

Stuart.

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3 minutes ago, stuart said:

Ive been happy enough with TR Shop supplied stuff but do keep original push rods ;) I have someone down here who re-sleeves them if required. Ive no experience of Past Parts more than supplies of seals.

Stuart.

Thanks Stuart I'm sure the recommendation will help a lot of folk searching for advice in the future. 

Andy

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Hi All,

Yes, all my fault. I know Stuart and others mentioned rogue master cylinder push rods but I was fixated on it being a slave cylinder problem. Stupid I know but a lesson learnt.

Sorry for prolonging the topic. Do we still have a PQI that looks at such things?

My master cylinder looks very clean but with the circlip removed and pushing the piston back and forth it doesn't want to come out. When the piston is pushed back and then released it springs back with some force but there is a metallic sound as if it is hitting a lip, which isn't case. I am not going to mess about it with it any more and take the point that if I need to change the seal (hopefully in many years time)  I'll remove the master cylinder from the car and give it a good bang on the bench.

Thanks you all again

Regards

Les

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I have contacted Moss and Rimmers for the dimensions, for the master cylinder push rod lengths and slave rod length for TR5/6's

Master cylinder push rod, right hand drive, Part No 122296 measures 78mm, from the domed end to the centre of the pin hole,

Master cylinder push rod left hand drive, Part No 148607 measures 73.5mm, from the domed end to the centre of the pin hole.

Slave cylinder push rod Part No 138572 is 147mm, from the end to the centre of the pin hole.

Moderators,

Is there a way we could keep these dimension locked somewhere for future referral, it does seem to cause some confusion at times.

John

 

    

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2 hours ago, John L said:

Master cylinder push rod, right hand drive, Part No 122296 measures 78mm, from the domed end to the centre of the pin hole

Sorry John 

But they have either measured it incorrectly or are now supplying a different version of the part. I have said part from Rimmers still in the bag with the label and its defiantly for a RHD car measuring 82mm. It will lengthen but is at its shortest length due to no further threads.

Andy

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Andy

I dont know where you get your dimensions from, but the rod 122296 is a solid rod and not adjustable, perhaps you could post a picture of your rod to clarify please.

John

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Hi John 

Old 122296 rod top and new with the bag it came. Both 82mm new is adjustable for a RHD 0.7" MC so I'm as confused as you now! Same part number for 250, TR5 and 6.

Andy 

IMG_1752.jpeg

Edited by PodOne
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2 minutes ago, PodOne said:

Hi John 

Old 122296 rod top and new with the bag it came. Both 82mm new is adjustable for a RHD 0.7" MC so I'm as confused as you now! Same part number for 250, TR5 and 6.

Andy 

IMG_1752.jpeg

Andy std is not adjustable 

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47 minutes ago, ntc said:

Andy std is not adjustable 

Ok but this one is capable of been adjusted and is the same 82mm length as the other taken from my MC, so is 82mm correct or 78mm? Strange I have two the same length claiming the correct part number.

Just looked at the Rimmer's site and the pic of "Push Rod Assembly - LHD - 148607" for a 0.7" MC looks very much like to one I was sent as a 122296 my guess is they have mixed them up in the parts bins! How I've got two the same is I suspect that the car I have arrived mostly in boxes so its possible a LHD MC/rod was sourced in error? That said the LHD is even shorter.

Said it before never buy from Rimmers if there is an alternative :angry: 

I used the same reference points quoted by John for measuring and got 82mm I'll recheck my vernier calliper and remeasure and report back.

Andy

Edited by PodOne
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Hi All,

The plot thickens. I ordered a 122296 from Rimmers and this arrived today. 82mm length.

This is despite them telling me

Hello Sir

The Part Measures 78mm.

Kind Regards

Rimmer Bros

I took a punt that they can't measure based on Andy's post. Nice chunky bit of kit though.

Regards

Les

Rimmer 122296.JPG

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