hi, my son has recently purchased a def 90 on a l plate 1994, he had a prob with brakes, the pedal was getting harder during applications so i had a look (being a hgv fitter) rear pads/discs us, the front pads are almost new so as i had the ns/f wheel off i prised the pads back to make sure the pistons were free which they were, i asked my son to operate the brake pedal to get the pistons back to their operating position but every time the pedal was lifted the pistons would retract so i had to back bleed the brakes to obtain pressure which i got, i suspected a faulty mas cyl, he ran the vehicle that afteroon when the front brakes decided to bind heavily, he got the vehicle home, brake pedal pressure was nil, i ordered & fit a new mas cyl, good pressure , no bind but doesnt have servo assistance or very little, i took the pipe off the servo, ran the engine & seems to have plenty of suction, is there any way to check the servo ? is the brake pedal rod to servo adjustable ?
i did not bleed the brakes when i fit the cyl as pressure was instant but lacks a bit @ rear

 

Have you checked the servo non-return valve? That's about all you can service on the servos. I suppose you could try manually applying vacuum to the servo and see if that works.

 

hi tom,no i havent tried the valve as yet but i will see if i can get 1 tommorow

thanks