Can anyone provide cross reference to Girling (or other) for the Jaguar Mark V late brake slave cylinders: H.3150 Front Wheel Cylinder Assembly, LH; H.3151 Front Wheel Cylinder Assembly, RH; H.3152 Rear Wheel Cylinder Assembly, LH; and H.3153 Rear Wheel Cylinder Assembly, RH? Even cross references for the bodies H.3164, H.3165, H.3157, H.3158 respectively would help.
I’m tackling some of the brakes while the car is up for the front suspension refresh. Looks like a couple of the brake cylinders are frozen though the car has been driving and stopping acceptably.
Girling made some changes in their numbering system later. I’ve found a Girling parts book which claims the 390172 is for the rear (no reference to LH/RH) and 390250 is for front (again no LH/RH reference and picture is not similar to ones in the car) and 64067515 is master cylinder (which does seem correct).
A bit confusing here for me. Cordell has a couple of parts, I have rebuild kits, but am worried about taking apart the system without knowing the parts needed or available that are not in my rebuild kit supply. A couple of frozen cylinders on a system working acceptably is better than no drivebility.
I am addressing a similar problem of trying to find replacement front brake cylinders for a MKV. While I cannot find anything fork MKV listed anywhere, I did look for replacement wheel cylinders for an XK120. While I do not have access to the relevant manuals to check, it is highly likely XK120s used the same Girling brakes components as MKV.
As I said, I have not yet had time to check out compatibility, but the price is so reasonable that it may be worth taking a shot on one just to check on interchangeability.
I see Peter beat me to it, but XK120 uses Lockheed parts where Mark V is Girling.
The Jaguar and Girling engineers went to a lot of trouble determining the master cylinder and wheel cylinder piston diameters, as well as brake pedal arm length and location of the operating clevis on the arm, all to get a proper balance front to rear under hard braking, and that all four wheels would lock up at about the same pedal force. The best braking is actually achieved when you ALMOST lock up the wheels. If you have that, then improved braking distance is related to choice of tires.
If you are going to convert to some other wheel cylinders, you need to match the piston diameters. Otherwise your force applied at the front and rear shoes will not be correct.
The fronts are 1" diameter and the rears are 1-1/8" diameter.
The main trick is getting the old pistons out without wrecking anything else.
Use the coefficients of thermal expansion to your advantage. Aluminum is 21-24 micro inches per inch per degree Kelvin, higher than steel at 11-12.5, so you can heat up the aluminum housing with a propane torch and it will expand more than the steel piston, enough to get some penetrating oil in there.
I flex-honed the housings, then finished off with Scotchbrite wrapped on the hone.
I found new rubber cups in both sizes UP1499 and UP2936 at Napa Auto Parts.
I made new pistons from stainless steel round bar stock from McMaster-Carr.
I made new hoods from stainless steel 1-1/2" tubing caps #10F-24 from Truly Tubular.
The square bars on the hoods are steel square keys.
I found it best to drill a 3/8" hole in the hood, center it on the piston, clamp it, weld through the hole, grind the weld flush, then clamp on the key bars and weld them just at the ends, finishing off the groove with a hand file. A MIG welder with .030" steel wire and CO2 worked fine for this.
I got new hoses from EL Johnston www.brake-hose.com
New cupro-nickel tubing from www.inlinetube.com
I re-used all the original tube end nuts where I could, but where I needed new, I found Autozone only had fully threaded nuts BLF-10C-5, which did not work in the original brass tees, so I had to cut down about 1/8" of threads to thread root diameter in a lathe as per the originals.
I made double-inverted flare ends using special inverted flaring tools SER41594 from Napa.
Thanks for replies and ideas thus far. Hopefully someone will know the cross reference to later Girling codes, I’d like to try further on getting stock from somewhere. In the meantime, last week I started down a parallel path of taking a frozen cylinder off my parts car and testing the torch and Kroil approach. The cylinder is still frozen but a few more heat cycles may do it. Rob’s pictures show a very probable path to be taken here!
Here are some (assembly/body) numbers found so far.
For late Mark V
Front cylinders, Jaguar Right Hand (H.3150/H.3164) is Girling (390334/ )
Front cylinders, Jaguar Left Hand (H.3151/H.3165) is Girling (390335/ )
Rear cylinder, Jaguar Left Hand (H.3152/H.3157) is Girling (390172/301430)
Rear cylinder, Jaguar Right Hand (H.3153/H.3158) is Girling (390173/301440), repair kit SP2015?
Master cylinder is Girling 64067515 for late and early Mk V
For early Mark V
Front Left Hand is Girling 390250
Front Right Hand is Girling 390251
Rear Left Hand is Girling 390610, repair kit SP2046?
Rear Left Hand is Girling 390611
For late and early Mk V brake hoses are
Front Hose 3703931W
Rear Hose 3703923W
I had this problem in 2002-2008 when I needed working brakes to get the car MOT’d and registered in the UK.
Cross referencing does not help pricewise. The only other cars I found to have used the same Girling setup were Ferrari 194/212 Inter / Europa and Alfa Romeo 1900 and 6C2500, not exactly bargain hobby cars.
I have the original ones which I think can be resleeved to make work again. The problem also seems to be that the original casting is of such metal that it will react with the plain steel piston, especially if not used very often and if the fluid will be contaminated or has absorbed too much water, it’s just a matter of time!
