S1 4.2 Brakes.

Technical advice Q&A

Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#1 S1 4.2 Brakes.

Post by eTypeG » Sat Jan 26, 2019 10:11 pm

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 ?

Link:
BBcode:
HTML:
Hide post links
Show post links


christopher storey
Posts: 4753
Joined: Sun Mar 09, 2008 3:07 pm
Location: cheshire , england
Great Britain

#2 Re: S1 4.2 Brakes.

Post by christopher storey » Sun Jan 27, 2019 11:09 am

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

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#3 Re: S1 4.2 Brakes.

Post by eTypeG » Sun Jan 27, 2019 12:33 pm

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)?.

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Sarthe72
Posts: 225
Joined: Fri Oct 25, 2013 7:21 pm
Great Britain

#4 Re: S1 4.2 Brakes.

Post by Sarthe72 » Sun Jan 27, 2019 1:31 pm

Had the same problem on the XKSS. Get a service kit and it is a straightforward repair. The brakes will work much better!

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 5258
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#5 Re: S1 4.2 Brakes.

Post by mgcjag » Sun Jan 27, 2019 2:53 pm

Have you looked under your front carpet...Steve
Steve
1969 S2 2+2 & Building a C type replica

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#6 Re: S1 4.2 Brakes.

Post by eTypeG » Sun Jan 27, 2019 3:29 pm

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

Link:
BBcode:
HTML:
Hide post links
Show post links


christopher storey
Posts: 4753
Joined: Sun Mar 09, 2008 3:07 pm
Location: cheshire , england
Great Britain

#7 Re: S1 4.2 Brakes.

Post by christopher storey » Sun Jan 27, 2019 6:19 pm

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.

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#8 Re: S1 4.2 Brakes.

Post by eTypeG » Sun Jan 27, 2019 11:25 pm

Many thanks for the replies, I think I'll sort the servo/slave cylinder and master cylinder at the same time.

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

AshM
Posts: 381
Joined: Wed Dec 14, 2016 4:59 pm
Location: Edinburgh, Scotland
Great Britain

#9 Re: S1 4.2 Brakes.

Post by AshM » 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
Series 2 FHC 1970
1R 20607

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#10 Re: S1 4.2 Brakes.

Post by eTypeG » Tue Jan 29, 2019 12:09 am

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 👍

Link:
BBcode:
HTML:
Hide post links
Show post links


Topic author
eTypeG
Posts: 151
Joined: Mon Oct 10, 2011 12:42 am
Location: Coventry
Great Britain

#11 Re: S1 4.2 Brakes.

Post by eTypeG » Tue Jan 29, 2019 10:43 pm

What finish should the brake servo/slave cylinder and brake master cylinder have ?

Link:
BBcode:
HTML:
Hide post links
Show post links


christopher storey
Posts: 4753
Joined: Sun Mar 09, 2008 3:07 pm
Location: cheshire , england
Great Britain

#12 Re: S1 4.2 Brakes.

Post by christopher storey » Wed Jan 30, 2019 10:14 am

Generally speaking, they are "blacked" cast iron, but many people paint them

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

AshM
Posts: 381
Joined: Wed Dec 14, 2016 4:59 pm
Location: Edinburgh, Scotland
Great Britain

#13 Re: S1 4.2 Brakes.

Post by AshM » Wed Jan 30, 2019 5:35 pm

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


Image
Series 2 FHC 1970
1R 20607

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic