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#1 S1 4.2 Brakes.

Posted: Sat Jan 26, 2019 10:11 pm
by eTypeG
The brake pedal on my 1965 4.2 FHC 4.2 (RHD) has become spongy, havent driven the car for a few months and noticed the brade fluid level has dropped in both bottles (one more than the other). Where would the fluid go? (as its not on the floor). Also which components will need sorting ?

#2 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 11:09 am
by christopher storey
If there are no external leaks, then a leak into the remote servo is the likely problem . A fairly good sign of this is white smoke with the engine running and the servo repeatedly operated. What happens is that if the cylinder seals fail on the shuttle in the " servo master cylinder ", the fluid goes backwards into the servo chamber. It is not a difficult job to repair these , but try to avoid the errant fluid getting on any paintwork while you are getting the servo out , and if it does wash it off immediately

#3 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 12:33 pm
by eTypeG
Thank you so muc for the reply, I have looked around the car and in it i can't see any fluid. But how could the fluid bottle empty on a parked car with the brake servo on the passenger side of the car and the fluid bottle on the drivers side (RHD)?.

#4 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 1:31 pm
by Sarthe72
Had the same problem on the XKSS. Get a service kit and it is a straightforward repair. The brakes will work much better!

#5 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 2:53 pm
by mgcjag
Have you looked under your front carpet...Steve

#6 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 3:29 pm
by eTypeG
mgcjag wrote:
Sun Jan 27, 2019 2:53 pm
Have you looked under your front carpet...Steve
Yes under the drivers side i have and no fluid found

#7 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 6:19 pm
by christopher storey
The fluid gets contained in the vacuum chamber of the servo, which is why there is no apparent ( external ) leakage . Once you take the servo off the car, you probably will hear it sloshing around inside !! Note that the two reservoirs both can drain into the servo, because if the servo cylinder is leaking, each time you press the pedal the master cylinder reservoir replenishes some of the absent fluid in the servo cylinder . The diagram in the workshop manual ( see the knowledge base here if you have not got one http://redirect.viglink.com/?format=go& ... f%3Fdl%3D1 ) is very helpful in showing you how it all works, even if a towel round the head is useful in studying it. Pages LY s 2 and 3 refer, and although these are for the S2, the S1 is the same except that in some cases the front and rear circuits are transposed.

#8 Re: S1 4.2 Brakes.

Posted: Sun Jan 27, 2019 11:25 pm
by eTypeG
Many thanks for the replies, I think I'll sort the servo/slave cylinder and master cylinder at the same time.

#9 Re: S1 4.2 Brakes.

Posted: Mon Jan 28, 2019 4:18 pm
by AshM
Just had all of my Brake, Clutch and Brake Servo Master Cylinders refurbished at Past Parts. Including relining the cylinders in Stainless Steel - absolutely delighted with the job. And so much better than replacing with new parts.

Just a thought...

Best
Ash

#10 Re: S1 4.2 Brakes.

Posted: Tue Jan 29, 2019 12:09 am
by eTypeG
AshM wrote:
Mon Jan 28, 2019 4:18 pm
Just had all of my Brake, Clutch and Brake Servo Master Cylinders refurbished at Past Parts. Including relining the cylinders in Stainless Steel - absolutely delighted with the job. And so much better than replacing with new parts.

Just a thought...

Best
Ash
Thank you so much, exactly what I was looking for 👍

#11 Re: S1 4.2 Brakes.

Posted: Tue Jan 29, 2019 10:43 pm
by eTypeG
What finish should the brake servo/slave cylinder and brake master cylinder have ?

#12 Re: S1 4.2 Brakes.

Posted: Wed Jan 30, 2019 10:14 am
by christopher storey
Generally speaking, they are "blacked" cast iron, but many people paint them

#13 Re: S1 4.2 Brakes.

Posted: Wed Jan 30, 2019 5:35 pm
by AshM
Here are how mine came back from Past Parts - Brake Master and Clutch Slave zinc coated. Black Powder for the Brake Servo Cylinder and the Clutch Master is alloy so cannot be coated so just sand blasted.

They all look great.

Best
Ash


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