Better Beaters - Building Cars and Daily Drivers

Gimme a brake! Part One of an extended series. 

(This was post was written quite a while ago, I'm not sure where I'm headed with this subject.)

Thinking about brakes and my Mark VII.  There will be a lot of ramblings and digressions in this presentation!

If only my old Jaguar was like any old Ford, restoration parts would be just a click away on the internet.

There are some parts easily available. I bought wheel cylinder kits without too much trouble. 

But the hard parts like brake drums and especially master cylinders are pretty much unavailable. 

They can be rebuilt, re sleeved, but at quite a cost. Then you've invested quite a bit of money into a obsolete brake system. 

If cost were not a factor.... I'd just send them away and hope for the best.

I've already dismantled the brake at each wheel, cleaned and re-kitted the wheel cylinders. I ran into problems with the master cylinders, I couldn't disassemble them.

They sit there mocking my efforts looking like a pair of dirty rusty little potatoes.

The easiest course of action would be to rebuild everything as original. 

I thought that I might be able to replace the master cylinder with a new modern replacement. I sent away for a Wilwood brake master. I just need to figure out how to attach it to the pedal linkage, and the hydraulic lines.

I discovered that the brake line is a commonly available size. I bought a fitting that I can use to adapt the m/c to the existing brake line. I would need to make an adaptor plate to mount the new m/c to the frame and see if the existing plunger could be adapted. 

If I can get it to work I'd be quite satisfied. The braking power of this car is superior to the same year American car, I think. 

There are British disc brake conversion kits available for the front brakes, that will work with the stock hydraulics.

The Coopercraft conversion looks like a quality item.

There was a home brew system posted on Jaguar Lovers website. Not a bolt on, but it uses fairly modern (late 1970's) parts but needs quite a bit of fabrication. 

This rotor has the same wheel lug spacing as my Jag.

The most important bit of info was the parts number for a rotor that will fit over the wheel hub. It will require the center bore to be opened up a bit, thereby permitting the use of the original hub and bearing set up. 

The Brit kits display a hub rotor assembly with  a dual piston caliper. this way the caliper can be solidly mounted as there is no need for movement. The caliper mounting bracket is quite small, bolting to the backing plate mount. 

The gold colored bracket bolts to the spindle.

There is an American hot rod company that sells disc brake conversion kits. They are cobbled up from an assortment of older production American components. Maybe not cutting edge, but the components are still available. This company's big contribution besides the research, is manufacturing the mounting brackets. These are a bit complicated, as they use typical single piston, sliding pin calipers. The OEM mountings are usually cast into the original spindle and are quite beefy. Obviously over engineered, but have you ever heard of one bending or braking?

This how a typical conversion looks.

The name of this company is Scarebird. Does that name inspire confidence? 

Permit me a lengthy digression.

Years ago I owned a '77 HD XLCR, purchased new. The cafe racer. It came with mag wheels and three disc brakes. The front assemblies were well engineered and were used for the next 25 years. The rear set up was very poor with the caliper attached to the swing arm with a sliding bracket. This wore out rapidly and developed a lot of slop. It still worked but it was noisy. It was the equivalent of the old banana caliper used in the early 70's HD front brakes. That reference will probably not mean anything to most of you. I was constantly looking for a better brake set up.

Now the brake system is a serious thing and important item to safety. However that didn't stop legions of Chopper riders in the past from removing the entire front brake system from an old Harley and replacing it with a spool hub, similar to a bicycle wheel sans any braking device! It did look very nice. Much time was spent lacing up brake hubs from Honda 50s and other small motorcycles to achieve the light look. Tiny drum brake assemblies were crafted by custom wheel companies so that the Chopper builder could comply with the law of the land in regards to equipment. Those set ups certainly didn't comply with the laws of physics!

Could this be considered a Death Trap?

My very first HD was a chopped '70 Sportster that sported a ten inch extended girder fork on a raked neck. It looked great, sporting that spool hub 21 inch wheel! Did it stop worth a damn? Of course not! But I rode it anyway, I figured that I could "adapt" my riding style. One of my cousins had a spool hub on his old Panhead chopper. My previous bike was a '76 Honda CB 750, the model that introduced front disc brakes to the motorcycle world! The first time that I tried to stop that Sportster in a hurry for a red light, I slid half way into the intersection. After enough close calls I felt something had to be done. But I rode it up to Mendocino on Highway One in it's original configuration after I rebuilt the entire bike! 

A fully functional brake, note the large caliper.
The brace provided a spot to mount the cafe racer fender.

I made some real improvements to my chopper. I replaced the entire front fork with a ten inch extended stock telescopic unit with a banana caliper brake. It carried a 21 inch narrow front rim laced to a stock hub. A brace was bolted to the lower legs and an aftermarket Hurst Airheart brake master cylinder was bolted to the bars. Since extended brake hoses weren't yet available, a length of plastic tubing, the kind used to hook up after market automotive oil pressure gauges was fitted. Once all the air was bled from the system it would lock up the front wheel. 

I took a bike that had been stripped of it's original drum front brake and replaced the entire front end. The later model incorporated a disc brake. This resulted in a complete improvement of even the stock design, Then I rode the cobbled up machine all the way through British Columbia and back. And survived.

Getting back to the XLCR, I found a replacement rear disc brake set up from Performance Machine. A new ventilated rotor attached in the stock location. A new two piston caliper was firmly mounted on one end of a long chromed plate the mounted on the axle with new spacers. The opposite end held a torque arm that was bolted to supplied bracket that was welded to the swing arm. A braided steel brake line was included. There was no fabrication required. 

It worked great and was a quality set up.

 Do I have an actual point that I'm trying to make? 

Yes, it is not inconceivable that extensive brake improvement can be made by the hobbyist to vital systems such as suspension systems, steering  and brakes. 

There are those that would not be comfortable making these changes. Understandable. But have you ever rebuilt your car's brakes? Removing the rotors, calipers, backing plates, shoes, lines, wheel cylinders etc? 

Yes, your life (and others!) are dependent on your careful and precise work. But it is usually within your limits.

Because of all the complexities of the decision, I have been putting this off for a long time! This has caused the project to grind to a complete stop better than a locked up caliper! 

I may have found a different course. 

After all, a project has to be economically viable as well as something that I can actually handle myself. I have learned of a company in California, Karp's out near Ontario. They specialize in re-sleeving brake components. I sent them a diagram of my master cylinders and they stated that they could repair them. I need to send the parts to them and they will provide a cost estimate. 

I may now have an avenue available to make some progress, but will I follow it?