Mk2 front brake upgrade and master cylinder capacity

Tom, if your upgrading the front, why don’t you do the rear as well by using the rear caliper of the XJ/XJS? 1.69" compared to the 1.5".

Norman - the original 2.125 Mk2 front Dunlop calipers will be going on the rear.

Theo - I like the idea of a dual circuit upgrade. Easy enough to find a dual circuit master cylinder, but the challenge will be the remote booster. Unless the booster had a dual circuit (which it doesn’t) this will remain the single point of failure and negate a dual circuit master. Would seem like most dual braking circuits the booster would need to come before the master.

Have you considered a setup with boosted fronts only? Maybe add balance valve to be able to fine-tune the front to rear bias. I plan on adding a balance valve to mine just for fine-tuning purposes. Problem is these only serve to decrease the rear braking only if I’m not mistaken. Maybe put one of these on the front circuit as you’d like need to dial down the front performance. Anyway, just a thought…but you could boost the front and have rears direct from the master.

Other option of course is no boost at all…,that would be easy but maybe not good performance wise.

I’ve thought about a compact style booster before the MC with some kind of lever to translate the upward motion from the pedal to a forward motion into a MC, but seems like a lot of engineering. My likely route with just be manual brakes, perhaps with a smaller bore MC to increase the pedal throw (and thereby decrease effort needed). There are many comments on here about how heavy the clutch pedal is when using a 10" spring clutch, but I find mine to be no problem at all. So maybe I could get away with manual brakes too…

Yeah, small diameter (but with more travel) master will give you some advantage. I adapted Tilton masters to mine for both the brake and clutch. Had to make a spacer to make it sit correctly. Advantage will be that both have more adjustability to set the pedal height and there’s a range of options with Tilton masters so if I need to I can go up or down a size easily. I’ll be using a remote reservoir for both brake and clutch. Would look at Tilton options if you haven’t already.

Although people do do this, you would need to keep in mind the front to rear bias. Standard on the Mk2 is about 2:1 whereas with your 1.75" Willwoods and the 2.125" on the rear you’re closer to 1.36:1.

So you probably need to fit a bias adjuster or you might find the rear of the car locking up.

Alternatively you could fit a set of 1.75" cylinders from an E Type which gives you exactly 2:1.

As an aside, I was intending to fit a set of Girling calipers from a Volvo 244 to my MK2.

These are easily modified to fit the standard Mk2/E Type hub carrier and I have them fitted on 2 of my E Types.

On one of the E’s I have ventilated discs and I bought what I thought was a set of correct discs for the S3 E Type, but unfortunately the offset doesn’t work with the Mk2 for some as yet undetermined reason.

So for the time being I’m sticking with the standard brakes.

As I said in earlier post, I intend to run adjustable bias as, with all the changes, there’s a good chance the bias won’t be correct. Adjustability will be my hedge :grinning:

I’m quite familiar with the Girling calipers having previously owned a series 2 e-type, and having upgraded my early Mk2 with later 420 uprights and calipers, but I’m not familiar with using Volvo 244 Girling parts. What sort of modification is required to fit the Volvo parts to an e-type? I’m interested because I have a series 1 project car I’m starting on soon. The Girling calipers used on e-types are pretty hard to find, but I would think the 244 parts would be pretty available.

https://studebaker-info.org/Tech/Brakes/Dun2volvo/tech0031sl.pdf

https://docplayer.net/33150042-Xke-brake-upgrade-using-volvo-calipers-brian-ternamian.html

Thanks for the link. I’ll keep that upgrade in mind.

It’s actually pretty easy to do. I have done a couple of sets drilling between the two cylinders with a 1/8" drill bit.

You then drill the 12mm mounting holes out to 1/2".

You need to be aware that the hydraulic pipe fittings are M10 metric, NOT imperial 3/8" UNF. These are very close in size. You will need to make up the J shaped feed pipe so it has a female 3/8" UNF fitting for the flexible hose on one end and a male M10 fitting on the other to go into the caliper. So it’s worth salvaging some of the hard line male fittings from the Volvo if you can.

I got the discs machined down by a brake place; $30 the pair, rather than fiddling with an angle grinder.

I paid $50 for a pair of calipers and the rebuild kits are available on EBay for maybe $150 including 8 new stainless pistons. Saves you about $600 or so in comparison to rebuilding stock calipers.

Be aware that there are 2 iterations of the calipers, one with 32mm pistons and the other with 38mm pistons. You want the 38mm pistons.

Hello Andrew, I am looking to do similar to my Mark2. How can I get hold of you please for a bit of a chat. I am in the Dandenong Ranges in Melbourne. cheers Chris

I’ve sent you a pm with my number.

How about fitting a master cylinder of a later XJ? I fitted one off an X300 (although the car is still being rebuilt so its not been tested yet). It was really easy to do and removes the need for a remote servo.

This is my write up from another forum.

Some people have said they can’t see why i’m bothering but having had the brakes fail on a 1966 S-Type due to a professionally rebuilt servo failing its something i’ve always been keen on.

It has been done a few times but I can’t find any photos that really show how so this is how I did it.

First I purchased a complete pedalbox, master cylinder and servo from a Jaguar XJ6 X300 from the mid 1990’s.

I played around with it a bit and found that there was no way it would fit with the X300 throttle pedal mounting (cast into the pedal box) in place and I want to use the original MK2 throttle system as it links to the carbs and gearbox with a system or rods.

I therefore cut these off with a disc cutter.

I tried it in place and found that the pedal box needed to be a fair bit lower that the picture below and also the brake pedal in an X300 cranks 50mm to the left which meant in a MK2 with the pedal box where I wanted it the pedal was 100mm too far to the left.

I looked into modifying the pedal but didn’t fancy it and so I ordered a left hand drive pedal from a breaker in the USA. You can see the difference here:

The little metal bar about halfway up is for the brake light switch on an X300 and its in the way so I chopped it off.

Then I fitted the original MK2 pedal box, master cylinder and thottle pedal to get the right positions:

Next I used a box, some wooden pieces as shims, some tape and marked the position on the floor pan so I could get the brake pedal in the right place.

Here is me fiddling with the X300 pedal box (note I did a final check with the old MK2 pedal box before welding it up to check that my spacer hadn’t moved or changed shape).

I cut a section out of the bulkhead to give clearance to the brake pedal, this was seam welded as its two panels overlapping in this area:

Then I bought some 3mm mild steel plate and made a piece to sit on the bulkhead, I cut this to shape, bent it to position the pedal box at the right angle and self tapping screwed it to the bulkhead and the pedal box to the plate:

I had previously removed the studs in the pedal box and drilled them out so I could bolt through, I had to cut the side of the pedal box mounting flange down and redrill one of the bolts further in. Then I welded captive nuts to the under side of the plate for all but the two nearest the bulkhead (as you cant’ get a spanner or socket on these to turn them so will be bolted through from inside the car with a crush tube/spacer.

Next I boxed in the plate and welded it to the bulkhead:

The nearley finished product (just waiting for some long nuts and crush tubes to be delivered.

The issues left to resolve are that the wiper motor needs to move slightly and the battery needs to find a new home. Otherwise it should fit well although if it were a 3.4, 3.8 or Daimler V8 it might be a bit different.

Very nice.

FWIW you can bend the cast steel pedals by heating them with oxy. We do this on our LHD to RHD conversions on E Types.

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