2 replies to this topic

[supersam47]

Hello.

 

I currently upgrading my brakes from drums all round to 7.5 disks on the front with a servo assist unit on my 1984 Austin mini sprite build.

I have installed a servo system and pedal box from a 1989 mini.

 

Question 1: Is the 1/2inch nut arrowed to adjust the clearance between the servo push rod and the master cylinder?

 

 arrow.jpg   33.48K   13 downloads

 

Question 2: Should i set this just with the pedal feel?

 

Question 3: The crank assembly (pictured no.19) is resting against the bulk head when the pedal is released. Should there be a bump-stop either on the peal or on the bulkhead? or should the brake light switch be adjusted till there is no longer a clearance issue?

 

 imagejgy.jpg   37.14K   4 downloads

 

 

 

 

 

 

 

 

 

[Stu1961]

1) The nut is there to lock the yoke in position on the servo rod, inside the servo there is a large cone shaped spring which is compressed when the brake pedal is pressed it acts as the return spring for both the servo diaphragm and brake pedal (There is no return spring at the brake pedal on a servo equipped car) the spring should be as (25) in the picture, this spring is solely for the clutch pedal.

 

2) The yoke should be set on the servo rod to give clearance on the bulkhead; if you don’t have clearance the brakes will be permanently applied to some degree as the servo and brake pedal cannot return fully to the rest position.

 

3) I would imagine the brake light switch would be adjusted last to suit the final position of the brake pedal when at its rest position.

 

Before I striped my servo down for refurb I took a measurement of the position of the locknut on the servo rod (10.5mm from the top of the nut to the shoulder on the rod where the thread stops/ends) this should give a reasonable starting point for initial adjustment. Have dry fitted the pedal box and servo to my shell and have no issues with clearance on the bulkhead using the afore mentioned dimension.

 

Hope this helps I would have posted a picture of the locknut position on the servo rod but I don’t have a lot of luck posting pictures on here.

Edited by Stu1961, 22 October 2017 - 07:20 PM.

[supersam47]

Thank you very much! I shall adjust as described!