After parking my MK2 for the winter I saw brake fluid leaking from the left front wheel. What could be the cause and what needs to be replaced?

 

probably the rubber hose leading to the caliper.

 

If it s not the rubber hose then you need to rebuild the caliper with new rubbers.

 

If the left front is leaking from either the rubber hose or the caliper seal I would also check the right side and the rears as they were all possibly serviced at the same time in the past and might need a full rebuild.

 

Wise advice! Brakes are best tackled all round & have a suspicious look at the Master cylinder & Servo/booster.

 

Last fall when I put my Mk2 in storage I noticed what appeared to be brake fluid leaking onto the floor beneath the left front wheel. Today I pulled the wheel to discover wheel bearing grease (about a ½ cup) inside the hub cap. The brake lines were intact as the brakes were redone about 3 years ago and the rubber lines looked as new.

Then I started the car and the brake pedal went to the floor. I replaced the master cylinder last summer and had the brakes bled. They were working fine when I put the car in storage. I checked the brake fluid reservoir and it was empty. There were no leaks visible anywhere under the car except for the left front wheel. Is there any way that brake fluid could be pumped into the wheel bearing?

 

In my 50+ years of Jag ownership I don't recall ever having a brake hose leak. However I have had plenty swell internally to complete blockages and have just obtained new hoses for my S3XJ6 because the rear callipers are holding on.
I am pretty sure Mark's LH front calliper is leaking and needs overhaul. In my MK2 I have had all callipers relined with stainless steel and I suggest that is the way to go as corrosion and pitting of the original callipers in a 60 year old car is almost a sure thing.
Otherwise new callipers are the way to go if money is no object.
I endorse Glyn's and Cass's advice on a complete check all round of the brake system.

 

Disappearing brake fluid means an internal leak into the large vacuum chamber in the brake booster.
If you keep topping it up, it will eventually get sucked into the intake manifold and cause plumes of white smoke when it's burned.
Won't hurt anything though unless it's DOT 5 silicone brake fluid.

And there is no way brake fluid can end up in the wheel bearing.

 

"And there is no way brake fluid can end up in the wheel bearing."

Jeff is spot on with his entire post. However if you find a sloppy mess in a wheel bearing it could be due to incompatible greases having been placed/mixed in that hub.

Never mix grease types when topping up a hub. Rather clean the bearing & hub & regrease completely. As an example a Calcium Complex grease is completely incompatible with straight lithium greases & will create a runny slop in the hub. Straight Lithium Stearate & 12-Hydroxystearate greases are the most common general purpose greases in an NLGI No 2 penetration on the planet.

 

It's the caliper. I'm having all 4 rebuilt. My car's mileage has not changed much. Unfortunately, that is not true of the flatbed.

 

Good practice & with single circuit brakes I would rebuild the master cylinder while you are about it. It is so easily accessed.