Has anyone tried to convert Mark 2 power brakes to HydroBoost? I found an older blog on the internet where someone was adding a XJ Series 3 pedal box to a Mark 2, but the blog ended in 2007 & never showed the product to completion.
Pictures?
Comments?
Regards,
Clyde Gantz

 

Isn't the hydroboost more for truck applications? I heard that since it uses the power steering pump for the added pressure there can be issues of the steering under hard braking? I would think the common upgrade of the Wilwood larger vented and more piston disc brakes would be the way to go.

 

Primaz,
Thanks for your reply. My main consideration is converting the 1960 Mark 2 to a power booster(ed) system with a dual master cylinder. Next is space - SBC, SBF, or 4.3 V6. I have not landed on the engine selection. The engine compartment gets very crowded, as I have followed your conversion with the SBC. And of course, but not last is braking power. I have seen Wilwood kits for the front from XK Unlimited(no affiliation), nothing for the rear. So I am trying to find out what others have done to eliminate the single brake line for front and rear, converting to isolated front and rear brakes, and stop the car with at least double the horse power that stock.
Regards,
Clyde Gantz

 

Clyde,


Most of the stopping power of any car is the front not the rear brakes. I think the basic upgraded Wilwood is plenty for most people and my assumption is that I should have no worries with my increased horsepower of 460 HP. It will be a couple of months before I start driving it so I will try to let you know my thoughts on the Wilwood but I am fairly confident that is plenty of brakes. The other thing I am doing which is good even for stock brakes is using all braided brake lines and better quality pads. My 3.8s came with stock disc brakes on the rear which to me are more than enough.


If you really want more brakes I think the next step would be to use a higher quality version of the 4 piston Wilwood and maybe check with Wilwood if they recommend any 6 piston versions that would work?

 

[QUOTE=primaz;882501]

My 3.8s came with stock disc brakes on the rear which to me are more than enough.
QUOTE]

Primas,
Does your 3.8s have a dual line master cylinder, could not tell from your pictures. Great build BTW.
Regards,

 

Clyde, I used a Series 3 XJ6 pedal box/master cylinder on my last Mark 2 project. Even with origial calipers there was a marked increase in assist and improved brake modulation. It was a simple install - fabricate a plate for the new pedal box and get the proper angle at the bulkhead to put the pedal where you want it - if I recall correctly this required an inch or two riser at the forward edge of the mounting plate. Sorry no pics as there were no digital cameras back then. This setup also allows you to get rid of the big servo and accumulator tank - not sure what they do except take up space. One of the easiest/best mods for these beasts imo. Good luck with your project.

 

Doug,
Thanks for the reply. Your comments match the old internet blog I found. It was dated 2006/07. Here's the link: Restoration of a 1962 Jaguar MkII: XJ6 Series III Pedalbox and Master Cylinder


Did you retain the original engine?
Regards,

 

The picture in that link is perfect. I don't remember the pedal offset being a problem - perhaps something to do with left vs right hand drive?

I retained the 3.8 in that project, though I did go with a straight port head. A modern steering rack and a 700 R4 were the other major upgrades - all helped but still didn't get the car anywhere near the level of a modern daily driver that I was looking for. For that I think a modern injected motor is a necessity, along with modern coilovers. At least that's my hope with the XJR transplant - only time will tell. Regards.