Repairs, Uncategorized
Comments 2

Jaguar XKE E-type Restoration: Bleeding the Brakes, What Fluid to Use and a Problem with the Master Cylinder

Now that the rear suspension was back up in the car and the drive line attached it was time to bleed the brakes in anticipation of firing the car up and seeing if all the pieces were back together correctly and the thing would run.  Bleeding the brakes is a process that starts at the back of the car and then moves to the front. The first caliper to be bled is the left hand rear, then right hand rear, then repeat for the front brakes. The front calipers are easy because they are so accessible. The rear brakes are another story. Because they are inboard and due to the geometry of the rear suspension the simplest way to do it is to remove the forward shock and spring combination.  Really, there is no other way to work the bleed valve properly. So, one has to jack up the car, remove the rear road wheels and pull the front shock/spring combos.  We had pre-loaded the cylinders with fluid.  In our case the car was already in the air and the wheels were off anyway.

Bleeding Rear Brake Caliper on Jaguar E-type XKE

Now a question often arises regarding which brake fluid to use in the E-type. I have used Dot 5 silicone fluid with no problems whatsoever in simple systems in classic cars such as the TR 3.  In s0me vehicles, such as classic Rolls Royces and Bentleys things get tricky and there are different special brake fluids for early post-war cars such as the Silver Dawn and Bentley MK VI and another fluid for the later Silver Shadow and T-Series. Expensive fluids I might add! For E-types most people seem to feel that it is best to stick with a Dot 3 or 4 (non-silicone)  fluid. The prescribed brake fluid for the cars was Girling/Catrol Crimson – which is not available any longer. I believe that Castrol GTLMA is acceptable – but I make no guarantees about this and warn you to do your own research and due diligence or get an expert to handle your brake issues. Jaguars are fast cars and brake failure can be deadly.

My son helped me with the bleeding and to make our life easier and the process more efficient we use a vacuum pump to get the fluid flowing through the new lines.  This is a real help after a system has been completely rebuilt and is dry.  Now once we had fluid to the calipers using the vacuum pump we began the usual process of one person opening the bleed screw and the other pushing the pedal down, then the first person closing the bleed screw and the second person allowing the pedal to come back up. Well, low and behold we found the brand new master cylinder was sticking and the shaft that connects the pedal to the piston simply went to the bottom of its drive and stayed there. You could pump the brake pedal all you wanted and nothing happened because the piston and shaft were not returning after the first stroke. I have never experienced this before with a brand new unit. We stopped operations, pulled the master cylinder and bench tested it – there was definitely a problem with the shaft and piston sticking at the bottom of the stoke… oh brother. Some time had passed between when I had purchased the new brake master cylinder and when I discovered it was malfunctioning. Fortunately – the very good folks at Welsh Enterprise were super friendly and understanding and shipped us a new unit immediately. The new master cylinder unit worked perfectly. Welsh is another class act in the Jaguar world!

Once the brakes were bled I put the rear shock/springs back in, put weight on the rear suspension and tightened up all the bushings. I was almost there in terms of getting the car running…

2 Comments

  1. CAREFUL WITH DOT 5 IT MAY WORK BUT i KNOW OF A JAG THAT WENT OVER THE SIDE IN THE LAGUNA SECA RACE BECAUSE IT TO SLIPPERY!!. USE CASTRO LMA DOT 4 I NEVER HAD ANY PROBLEM WITH THE CUSTOMARY THAT USE LMA. i REBUILD ABOUT 250 OF THE E- TYPE AND A LOT OF EARLY BRITISH CARS. iI HAVE BEEN DOING IT FOR 50 YEARS,iF THEY USE THE RIGHT FLUID NEVER HAVE A BOOSTER PROBLEM.

    Like

    • G M MacDonald says

      Thanks. A lot of folks find the DOT 5 (silicone based) does not work well with the older Jag hydraulics in any case.

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s