Clutch master cyl and hose .....

seight · Post by **seight** » Mon Nov 23, 2009 8:38 am

I need a new pushrod for a Girling master cylinder. Anyone know where I can get one? I've seen extended ones sold separately at Europa Spares but I'm not sure there's enough thread on it.

Also, I'm changing my clutch hose, should I be using -4 ?

thanks
Mike

gelmonkey · Post by **gelmonkey** » Mon Nov 23, 2009 9:10 am

Hi Mike
With regard to the pushrod can you not cut the thread to the length you need it to be?
The hose is fine at -4.Just make sure that it is fixed well to the chassis via a small bracket or similar.
Cheers
Paul

topcatcustom · Post by **topcatcustom** » Mon Nov 23, 2009 9:20 am

Can you not just weld a longer thread on it?

gelmonkey · Post by **gelmonkey** » Mon Nov 23, 2009 9:54 am

OI TC
are you stalking me?

topcatcustom · Post by **topcatcustom** » Mon Nov 23, 2009 10:13 am

gelmonkey · Post by **gelmonkey** » Mon Nov 23, 2009 11:30 am

So am at home again because it never stops raining down here!!!!

seight · Post by **seight** » Mon Nov 23, 2009 10:23 pm

I think I'll give the one from Europa a go. I'm a crap welder!
Trouble is the one that's in it has been shortened and doesn't quite give enough adjustment for my slave to work properly. When the pedal comes back up it doesn't allow the fluid back from the slave fully so next time you pump the pedal you are just sending more fluid to the slave until if pops out !
Mike

Ian Anderson · Post by **Ian Anderson** » Tue Nov 24, 2009 9:36 am

Longer pushrod?

I'd say shorter
Perhaps master piston is not returning enough to open the "fill" hole from reservoir

Or there is not enough return spring on the slave end thereby fully releasing pressure on the clutch mechanism

1/4 inch clutch pipe is good for quick changes so fluid can move more quickly than through standard brake pipe stuff

Ian

ian.stewart · Post by **ian.stewart** » Tue Nov 24, 2009 10:15 am

Ian Anderson wrote:Longer pushrod?

I'd say shorter
Perhaps master piston is not returning enough to open the "fill" hole from reservoir

Or there is not enough return spring on the slave end thereby fully releasing pressure on the clutch mechanism

1/4 inch clutch pipe is good for quick changes so fluid can move more quickly than through standard brake pipe stuff

Ian

Im with the smaller pipe, means less fluid to move less weight on leg, go to extremes, if this was the case race cars fitted with hydraulic brakes and clutches would be running big pipes,
I would be fitting -2, look inside the master or slave cyl, I would be surprised if there is a drilled hole entering or exiting thats much more than 2mm, so putting a bigger pipe on will not have any beneficial points

Ian Anderson · Post by **Ian Anderson** » Tue Nov 24, 2009 1:29 pm

Im with the smaller pipe, means less fluid to move less weight on leg, go to extremes, if this was the case race cars fitted with hydraulic brakes and clutches would be running big pipes,
I would be fitting -2, look inside the master or slave cyl, I would be surprised if there is a drilled hole entering or exiting thats much more than 2mm, so putting a bigger pipe on will not have any beneficial points[/quote]

Ian

If you have to move a slave 3/4 inch it will take x amount of fluid
To move this fluid through a pipe will take a finate amount of time
Put a restriction in the way and it will take longer to move the same amount of fluid (That presumes all other variables remain constant)
It may not be an issue on front engine cars but move the engine to the rear end and it does pose a problem and causes clutch drag / slip

Different story on brakes
You are not moving calipers 3/4 inches - more like 1/32 - 1/16th so amount of fluid that moves is a lot less hence the smaller diameter brake lines. (Unless you use recirculating brake set up when again you need the bigger diameter)

Ian

SuperV8 · Post by **SuperV8** » Tue Nov 24, 2009 1:48 pm

Most standard cars I know use 3/16 hose for the clutch. I don't know how that relates to -dash ? I think -3?

Not sure I agree with a smaller diameter being easier on the leg???

IMO the smaller the hose the harder on the leg. There would be more drag in the hose = harder to push. The smaller the hose, the more resistance to flow.

I second that:-
"If you have to move a slave 3/4 inch it will take x amount of fluid
To move this fluid through a pipe will take a finate amount of time
Put a restriction in the way and it will take longer to move the same amount of fluid (That presumes all other variables remain constant)
It may not be an issue on front engine cars but move the engine to the rear end and it does pose a problem and causes clutch drag / slip

Different story on brakes
You are not moving calipers 3/4 inches - more like 1/32 - 1/16th so amount of fluid that moves is a lot less hence the smaller diameter brake lines. (Unless you use recirculating brake set up when again you need the bigger diameter)
Ian"

Tom.

ian.stewart · Post by **ian.stewart** » Tue Nov 24, 2009 2:15 pm

Ian Anderson wrote:Im with the smaller pipe, means less fluid to move less weight on leg, go to extremes, if this was the case race cars fitted with hydraulic brakes and clutches would be running big pipes,
I would be fitting -2, look inside the master or slave cyl, I would be surprised if there is a drilled hole entering or exiting thats much more than 2mm, so putting a bigger pipe on will not have any beneficial points

Ian

Put a restriction in the way and it will take longer to move the same amount of fluid

Ian[/quote]
although I put it accross as the second part of the reply, This is the main point Im trying to put accross, look inside the cylinder where the fitting screws into the cylinder, its unusual to see a cylinder with much more than a 2mm hole feeding fluid from and to the cylinders,

seight · Post by **seight** » Wed Nov 25, 2009 4:35 pm

I'll give -3 a go.

I guess it really depends on the bore of the master cylinder. Big bore cylinder, small hose means harder pedal - I think ! My master is .7" bore, the slave is a Saab concentric type.

It is definitely a longer push rod that I need too. Mine's an integral reservoir master cylinder. They have a strange plunger setup where the fluid going to the slave comes from between the 2 plunger 'seals'. I think my pushrod has been shortened too much so (with my pedal box) it won't seal the hole to the reservoir. This means when the pedal comes back up it draws more fluid from the reservoir rather than back from the slave.

I adjusted the pedal so it's right on the end (one nut is hanging off actually) of the pushrod and the clutch works. But I would like a bit of spare thread in case I need to adjust it later.

Mike