Sunday, August 17, 2008

Brakes part deux

My post a couple of days ago talked about looking at the back brakes. I noted a few problems.
1. There was a crimp in the rear brake line - probably due to someone trying to tow the car with chains around the axle (even though there are tow hook spots on the back).
2. A leaking wheel cylinder.
3. The brake shoes were in the wrong way around, and some of the springs were aligned incorrectly.

So today I tackled these issues. I had ordered a new brake line from MossMotors. I also bought a new wheel cylinder from Advance Auto. You can get them online, but Advance could get me one in 24 hours with no shipping. Its worth bearing in mind that you might be able to get parts from your local auto parts store from time to time.

Before starting this project, I watched John Twists video on rear brakes again and took notes. Here is the video. Watch it over and over before you start!! I also used a Gunson Eezibleed - these are awesome - google it to get one.

First I dismantled the brakes. After jacking up and safely supporting the car on jack stands, I removed the brake shoes and springs. The cylinder is easy to get off, there is a U shaped spring clip on the back that holds it in place. You also have to remove the brake bleeder to get it off.

The new cylinder goes in pretty easily, although it is a bit of a pain getting that clip back in.

I put the shoes back in according to John Twists video. Basically one shoe is up, the other down. Also it is important to align the springs so that they don't interfere with other components.

The new brake line comes coiled. Its copper tubing with little nuts on the end that screw into the junction at one end (near the differential) and the wheel cylinder at the other end. You've got to be careful bending this so that it fits. I used the old tubing to get the basic shape and that worked pretty well.

Next, it is time to bleed the brakes. The Eezibleed hooks up to the spare tire and uses the air pressure to force brake fluid through the system. It literally took about 20 minutes to bleed the brakes.

The final part is adjusting the brakes. There is only one place to adjust brakes on an MGB and that is on the rear wheels. There is a square bolt that changes the spacing of the shoes. To set this bolt, first you tighten it until the wheels won't turn. Then jump in the car and pump the brakes. Hop out and see if the wheels turn. If they do, then re-tighten. If not back off the bolt a quarter turn. Hop in the car and pump the brakes again to see if the settings are good.

And while I had the car jacked up I tightened up the hand brake so that it only needs 4 or so clicks to be fully engaged.

Now the test drive!

Folks say that the stock MGB brakes are pretty good. I was previously unsure of this. I had never locked up the front wheels. Well, there are now black skid marks on the my street that attest to how keen my brakes are now. This service has certainly made a difference.

The whole thing took about 3 hours. Go ahead and do you brakes today if you haven't looked at them since getting the car!

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