Clutch slave cylinder

[jjc]

Just out of interest has anyone had to service the slave cylinder on a Mk2 GT6?  Putting the gearbox back by hoisting in engine and gear box together I forgot to put the push rod back in the cylinder.  As I have the gbox tunnel out it wasn't difficult to get at the slave cylinder fixing bolts but I can't see how you would do it if you didn't have the internals stripped.  Haynes of course just says unbolt the cylinder.  Just curious as to how you would service the slave cylinder as a job on its own  JJC

[johny]

Think you can bleed the slave with the cover in place doing it from the bulkhead side but thats it. If you need to remove it then the cover has to come off but then the same applies for overhauling the gear lever linkage or changing gearbox rubber mounts so once youve done it a few times its easy😁 

[dougbgt6]

The master cylinder to slave pipe has a loop in it, this is to allow for engine flexing. Fine in olden times, but after 50 years pipes go brittle. We have one at East Berks who's had a looping pipe fracture. I've replaced my pipe with a flexible armoured jobbie.

Doug

[Pete Lewis]

and dont forget the idea of fitting a brake hose and nipple to the bleed port so you can bleed from the engine bay

Pete

[dougbgt6]

Yes, indeed. A pain on a GT6, but worse on a Spitfire!

Doug

[Peter Truman]

1 hour ago, dougbgt6 said:

Yes, indeed. A pain on a GT6, but worse on a Spitfire!

Doug

Try a Dolly Sprint! a real pain in the ar*e

[jjc]

Yes that was the point of my post.  I'm (or was in my younger days) a TR driver.  TRs are much easier to keep going.  The GT6 was a revelation at first - bonnet off and you can get at everything.  But then came the slave cylinder issue.  An expert friend (proper experienced mechanic) when I asked how on earth do you get the slave cylinder off said - "would be very bad design if you had to either take the engine out or dismantle the inside of the car to service it".  He's right, it's either bad design or a commercial decision to use a slave cylinder already available.  They could have tapped the cylinder rather than tapping the bell housing.  Never again.  JJC

16 hours ago, Peter Truman said:

Try a Dolly Sprint! a real pain in the ar*e

 

18 hours ago, dougbgt6 said:

Yes, indeed. A pain on a GT6, but worse on a Spitfire!

Doug

 

[johny]

I dont understand really as the slave cylinder shouldnt need any more attention than plenty of other components (as Ive mentioned) which are equally inaccessable. Even if you could get it out the pushrod has to engage with the operating arm which would be almost impossible to do with the gearbox cover in place....

[Colin Lindsay]

True; I replaced mine on the Mk1 when I rebuilt the car and the same one was still going twenty years later. It's not a job that requires doing too often, so yes it may be fiddly but no more bother really than replacing the clutch, which also has to be done occasionally.

[johny]

I think what kills them is moisture in your hydraulic fluid and/or not operating the clutch for a long time. In both cases the bore can corrode either inside or outside the seal (or both) so that when used the rubber seal gets ripped and starts to leak.... 

[daverclasper]

On 12/10/2024 at 16:18, johny said:

I think what kills them is moisture in your hydraulic fluid and/or not operating the clutch for a long time. In both cases the bore can corrode either inside or outside the seal (or both) so that when used the rubber seal gets ripped and starts to leak.... 

Yes. though I think some modern, poor quality seals may have made mine fail after a few years. Changed the seals and so far these have lasted longer?

[dougbgt6]

On 12/10/2024 at 16:18, johny said:

I think what kills them is moisture in your hydraulic fluid and/or not operating the clutch for a long time. In both cases the bore can corrode either inside or outside the seal (or both) so that when used the rubber seal gets ripped and starts to leak.... 

The reason why the USA military developed silicone brake fluid, lots of vehicles sitting around for years then suddenly you need to fight a war. Water in the fluid can also boil and suddenly you got no brakes. 

You're supposed to change traditional fluid every couple of years. I recall Uncle Pete got one of these (£2.50 on Fleabay)  and tested the whole of Herts & Beds one club night, an embarrassing number of failures.

[Peter Truman]

Did the same testing on our club fleet of classics around 50 percent were over 2percent advised we wouldn’t be authorising their club permit next year if the brakes weren’t checked and fluid changed. Club permit is effectively cheap rego and third party insurance but restricted number of days it can be used.

The daughtersSpit is on Dot4 and it gets changed every 3 years or sooner if repairs needed my Vitesse is on Dot 5 silicon What is the recommended flush period obviously water isn’t an issue the fluid still looks clean syringed some out and checked colour with a new bottle of DOT5.

Interesting our daily driver is 4 years old next feb and I’m expecting Mazda will advise a full bleed is necessary but a test the other night the moisture was only 1 percent so all ok, maybe it’s our climate and the cars always garaged. I’ll go to my brake chappie he only charges $70 for a full bleed! Not worth getting my hands dirty!

[johny]

Modern cars have a rubber diaphragm in the master cylinder cap which allows changes of fluid level but no contact with fresh air. Unfortunately our oldies dont so moisture laden air is free to enter repeatedly everytime the brakes are operated or even if just the ambient temperature changes☹️ Then of course a high humidity climate will make things even worse for us!

[Colin Lindsay]

My modern also has a 'change brake fluid' symbol on the dash; you can cheat to make it extinguish but it's safer to flush the system and replace with new fluid, for peace of mind and for all the bother it really causes doing it.

[johny]

Surely its only based on mileage or time not brake fluid condition Colin?

[Colin Lindsay]

1 hour ago, johny said:

Surely its only based on mileage or time not brake fluid condition Colin?

I reckon so; I should search online and see what the time period actually is - in fact I just did and they reckon every two years, or three on the latest models. It dates from the first assembly of the car, not the sale date. There's also a service indicator that ticks down from green to orange to red but no idea if that's based on mileage, running hours, or just time.

[dougbgt6]

2 hours ago, johny said:

Surely its only based on mileage or time not brake fluid condition Colin?

I don't see why it wouldn't have an internal tester, the cheapest on Fleabay is £2.50, doesn't cost a lot.

My Fiesta service indicator lit up on the way to the first MOT. It's done that two years running, the wretched thing is goading me.

Doug

[johny]

6 minutes ago, dougbgt6 said:

I don't see why it wouldn't have an internal tester, the cheapest on Fleabay is £2.50, doesn't cost a lot.

Could do but would it still have a time constraint as well so you change it even if it is self testing good?

[dougbgt6]

Probably, everybody wants you to buy more stuff whether you need it or not! 

Doug