S Type Brake Woes

[cjhull]

Hi all

Picked up S Type yesterday afternoon.

Brake Pedal is hard, now the ex owener has had a replacement servo put on (used), along with replacement vacuum pump and replacement pipework. Brakes are locked on, on front wheels. Brake lights are also on unless you lift the pedal slightly up. Brake pedal is hard, you can apply if you push hard and you do get brakes. 

 

Shot Servo? Sometghing other? 

Electronic type servo I believe.

Car is an 05 2.7 TDV6 mileage around 108k.

Thanks

[Jaguar Owners Club]

Had to replace a servo on diesel S-Type once before as was corroded and leaking pressure.
Fitted another one (later type as used on XF) and worked fine.
However, there is a actuating pushrod between the brake pedal and the servo which I believe it adjustable so if the replacment one is not set correctly then this could be the issue.
Would necessitate removal of the brake pedal pushrod (from the underside of the dashboard) and making an adjustment to the length which would release the hydraulic pressure off the braking system.

[cjhull]

On 2/4/2021 at 10:04 AM, Jaguar Owners Club said:

Had to replace a servo on diesel S-Type once before as was corroded and leaking pressure.
Fitted another one (later type as used on XF) and worked fine.
However, there is a actuating pushrod between the brake pedal and the servo which I believe it adjustable so if the replacment one is not set correctly then this could be the issue.
Would necessitate removal of the brake pedal pushrod (from the underside of the dashboard) and making an adjustment to the length which would release the hydraulic pressure off the braking system.

Hi mate thanks for that.

Er, where do I start... Took master cylinder off today and double checked everything and fitted it all back together. Now the brakes are not locked on but the brakes feel very wooden, Push the brake pedal down and not a lot happens almost like theres no assitance. Its a lot better than it was and on the brake roller everything was in limits barring a sticking/dragging caliper on the nearside. 

On thwe Bosch diagnostics for some reason a fault came back but no code and it just said that the Brake Booster Switch was 'Open' or 'Closed' and when brake applied did not change so suspect the Brake Booster Switch/Sensor might be faulty...not sure where that is located.

 

[Jaguar Owners Club]

I think it would be worth removing the servo which isn't too difficult to remove and inspect the valve where the pushrod goes into and see if there is corrosion in there...if so replace the servo

[cjhull]

Update 

 

Car went in for MOT and passed 🙂 after I got a new caliper on nearside front fitted as it was dragging.

 

Brake pedal still feels quite hard, and also, the pedal keeps sticking to the point the brake lights stay on - so when you lift your foot off the brake it does not come all the way to the top and holds the brakes on slightly and the brake lights... and I have to lift the pedal with left foot. Pedal seems louder than what I would expect as well....is this c ase of adjustment and lubrication?

Would that still point to a servo problem? I've tested the servo as far as I can without removing it off of the car. Brakes do feel 'wooden'. But whether its linked to Servo or not I have no idea. 

I keep getting DSC Fault as well... which can be linked to Servo in some cases.

 

Am I going to have to bite the bullet and grab a brand new servo from Jag?

Part Number on mine is 2R83-2005-BB. 

 

Thanks in advance.