Advice on brakes

[aksportscars]

Just measured the rover 25 servo and master cylinder 185mm from servo face where it bolts to bulkhead to the end of the master cylinder, and 235mm in diameter.
Not sure you will find anything much smaller, maybe Mazda mx5 or old mini's.

Jon
AK

[GDCobra]

Just measured the rover 25 servo and master cylinder 185mm from servo face where it bolts to bulkhead to the end of the master cylinder, and 235mm in diameter.
Not sure you will find anything much smaller, maybe Mazda mx5 or old mini's.

Jon
AK

Wow! That actually sounds hopefull in terms of length at least, unfortunately it sounds like the diameter would be a problem although possibly not insurmountable, may be possible to offset the push-rod one brake or clutch.

Do you have any idea what the bore size of the master-cylinder is?

The only think whch sounds a bit worrying is that presumably the master cylinder must be very short (185mm overall indicates cylinder must only be about 100mm or so maximum) I wonder if this would have enough stroke to operate the Jaguar calipers and not bottom out. But obviously it works in a Rover 25 so presumably could be made to work here.

[aksportscars]

Hi,

We use this system on all our AK's with the standard XJ6 and XJ40 brakes, we also use this on our big brake kits with 6 pot fronts and 4 pot rears, so it will work fine on your set up. They offer two bore sizes 22.7mm and 23.8mm, but both work .

Jon

[GDCobra]

Hi,

We use this system on all our AK's with the standard XJ6 and XJ40 brakes, we also use this on our big brake kits with 6 pot fronts and 4 pot rears, so it will work fine on your set up. They offer two bore sizes 22.7mm and 23.8mm, but both work .

Jon

Thanks for the information Jon, that sounds like it would be worth investigating, the 22.7 is only slightly larger than standard and even 23.8 is not too much of a stretch IMO (about 4 & 13% drop in line pressure respectively), wtih the additional assistance from the servo it would probably be of benefit to go for the larger one to reduce pedal travel.

Not even an expensive item from what I can see either.

I'm getting tempted myself now!

[Alan M]

It was years ago that I found the Polo unit GD, it was a s/hand one just to see if it would fit but once I decided against it I binned it and I haven’t been able to find a similar one again.
I take your point about the efficiency of the system, however the whole system is effectively new, like you I don’t mind the pedal pressure being higher than a modern car and under normal braking it performs well, even under heavy braking its progressive and pulls up well but the pedal pressure is just too high by the time I get to the point where it feels like it might lock up, which makes me think it’s down to pedal ratio and m/c diameter.
I’m 6’4 so when I rebuilt the car I moved the firewall forward by 50mm which gives me even less space to play with than you! I haven’t done any measuring yet but using your figures the unit that Jon has mentioned would just about fit although I would probably have to modify the cover panel as you suggested.
As you rightly say the distance between the centre lines of the two cylinders is the other issue but I wonder if the clutch m/c could be spaced forward enough to clear the front edge of the servo body?

Jon, I can only echo what GD has said, your experience with the Rover 25 unit plus the measurements is really useful, this would be a far simpler (and neater) solution than a remote servo!
many thanks
Alan