Brake Balance Valve/Regulator or Not

BarryS · Dec 12th, 2013, 09:42

Two cars, 122S 1964 and 122S 1966. Both single circuit brakes, both with all new brakes, same master cylinders, calipers, discs, pads, drums, shoes, adjusters, wheel cylinders, Lockheed remote servo.

Both cars brake very well but I have been trying to get the pedal feel on the 64 car the same as the 66 but have failed. The 66 car has, for me, perfect pedal feel. Strong high pedal, great braking modulation.

Last evening, I stumbled across a fundamental difference between the cars. The 66 car has an original brake balance valve/regulator plumbed into the rear brakes. The 64 car does not. Logic seems to indicate that this is this feature responsible for making the 66 cars brakes feel better.

What do other people have? Did you fit different bore rear wheel cylinders in conjunction with a remote servo and no brake balance valve? or did you fit a brake balance valve/regulator as well?

Assuming that original brake balance valves are now not obtainable and/or mega expensive, does anyone know of a suitable cost-effective aftermarket item?

Feedback would be much appreciated.

Barry

Derek UK · Dec 12th, 2013, 22:06

If both your regulated and non regulated cars have the same rear cylinders, one of them is wrong. The earlier car should have 7/8" cylinders and the later regulated car should have 1" cylinders.

classicswede · Dec 12th, 2013, 23:14

The 64 is likely to have originally had drums on the front.

BarryS · Dec 13th, 2013, 08:38

Thanks for the feedback.

Classicswede - I believe it to be a 64 122S front disc model. It saw extensive work by a previous owner back in 2002 with non-servo disc set up. I've now replaced all brakes components, adding a remote servo.

Derek - Good point, replacement wheel cylinders for this car were supplied as 7/8" on the invoice because I was fitting a servo to a previously non-servo car but I'll double check in case there was an error.

Bladerider · Dec 13th, 2013, 14:02

Fitted Servo to my '66 122S which has a balance valve. Changed the rear cylinders to smaller diameter on the advice of Tony Barrett. Haven't had it on the road yet, so can't really comment on efficiency.

JP 1800 · Dec 13th, 2013, 16:14

As stated there are 2 different sizes for the rear cylinders depending on which car you have, for non servo cars 1" rear cylinders are used and for servo cars 7/8" is used. You have to be methodical to get a good strong brake feeling on these cars by eliminating any air in the system but also ensuring that the rubber lines are good and also that the master cylinder is in good order.

classicswede · Dec 13th, 2013, 18:43

And make sure the rear brake shoes are correctly adjusted as they do affect pedal feel

Dec 12th, 2013, 09:42	#1
BarryS Junior Member Last Online: Jun 3rd, 2024 11:36 Join Date: Apr 2006 Location: Dorchester	Brake Balance Valve/Regulator or Not Two cars, 122S 1964 and 122S 1966. Both single circuit brakes, both with all new brakes, same master cylinders, calipers, discs, pads, drums, shoes, adjusters, wheel cylinders, Lockheed remote servo. Both cars brake very well but I have been trying to get the pedal feel on the 64 car the same as the 66 but have failed. The 66 car has, for me, perfect pedal feel. Strong high pedal, great braking modulation. Last evening, I stumbled across a fundamental difference between the cars. The 66 car has an original brake balance valve/regulator plumbed into the rear brakes. The 64 car does not. Logic seems to indicate that this is this feature responsible for making the 66 cars brakes feel better. What do other people have? Did you fit different bore rear wheel cylinders in conjunction with a remote servo and no brake balance valve? or did you fit a brake balance valve/regulator as well? Assuming that original brake balance valves are now not obtainable and/or mega expensive, does anyone know of a suitable cost-effective aftermarket item? Feedback would be much appreciated. Barry

Dec 12th, 2013, 23:14	#3
classicswede Trader Volvo in my veins Last Online: Yesterday 21:49 Join Date: Dec 2004 Location: Anglesey	The 64 is likely to have originally had drums on the front. __________________ http://www.classicswede.org www.classicswede.co.uk

Dec 13th, 2013, 14:02	#5
Bladerider Amazoniac Last Online: Nov 18th, 2014 13:53 Join Date: Oct 2010 Location: Essex	Fitted Servo to my '66 122S which has a balance valve. Changed the rear cylinders to smaller diameter on the advice of Tony Barrett. Haven't had it on the road yet, so can't really comment on efficiency. __________________ 1966 122S registered 1/1/67. Metallic Blue moving to original Horizon Blue during restore like this one.

Dec 13th, 2013, 18:43	#7
classicswede Trader Volvo in my veins Last Online: Yesterday 21:49 Join Date: Dec 2004 Location: Anglesey	And make sure the rear brake shoes are correctly adjusted as they do affect pedal feel __________________ http://www.classicswede.org www.classicswede.co.uk

Dec 12th, 2013, 22:06	#2
Derek UK VOC Member Last Online: Yesterday 18:09 Join Date: Jul 2006 Location: Chatham	If both your regulated and non regulated cars have the same rear cylinders, one of them is wrong. The earlier car should have 7/8" cylinders and the later regulated car should have 1" cylinders.

Dec 13th, 2013, 08:38	#4
BarryS Junior Member Last Online: Jun 3rd, 2024 11:36 Join Date: Apr 2006 Location: Dorchester	Thanks for the feedback. Classicswede - I believe it to be a 64 122S front disc model. It saw extensive work by a previous owner back in 2002 with non-servo disc set up. I've now replaced all brakes components, adding a remote servo. Derek - Good point, replacement wheel cylinders for this car were supplied as 7/8" on the invoice because I was fitting a servo to a previously non-servo car but I'll double check in case there was an error.

Dec 13th, 2013, 16:14	#6
JP 1800 Master Member Last Online: May 5th, 2024 08:41 Join Date: Aug 2009 Location: Dublin	As stated there are 2 different sizes for the rear cylinders depending on which car you have, for non servo cars 1" rear cylinders are used and for servo cars 7/8" is used. You have to be methodical to get a good strong brake feeling on these cars by eliminating any air in the system but also ensuring that the rubber lines are good and also that the master cylinder is in good order.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)