Bleeding the brakes

Hi all,

I have just redone the brakes on my 77 B. I have replaced the rear cylinders, the front calipers, the rubber hoses front and back, new shoes, springs, rotors and pads. I have bled the brakes until there is new fluid coming from all four corners. I just can't seem to get them to tighten up. I have adjusted the rear so that they just have a little drag on them. A friend of mine suggested loosening the to main connections at the MC slightly while pressing the peddle in to see if I have a bubble trapped at the top. Did that with no change. I must be using a left handed wrench. Any thoughts? Thanks Dean

Hubby and I just did this last week after he replaced the master cylinder for my brakes on the 80 MGB. I sat in the car and would pump the brakes up and down and then he would tell me to hold it while he loosened the valve at each wheel and let the air and old fluid out with a little clear hose and a glass. He would then close the valve and do it over and over until there was no air. In between pumping I had to make sure the master cylinder was full of " DOT 3 " brake fluid. It was real easy and only took a short time.

The order of bleeding was driver's side rear, passenger side rear, passenger side front, and driver's side front. Piece of cake and I have great brakes and new fluid through all the lines :) :)

When I did mine, I ended up disconnecting the brake line from the MC and bleeding it, reconnecting and then starting from the wheel furthest from the MC. I am sure others who know more than me will soon chime in. Bleeding brakes and clutches on any LBC is quite a job, I'd say!

What kind of brake fluid are you using?
Are the bleeders located at the top of the calipers?
What method are you using to bleed the brakes?

Dean,
If all else fails, make sure that you bleed the salve cylinder as well. Be sure to push the "push rod" in as far as you can while you crack the bleed screw. It is not uncommon to have bubbles get trapped in the area between the push rod and the piston after you have changed everything out. Forcing the push rod forward while you bleed at the same time will usually get rid of the trapped air.

Kimberly Wrote:

Another vote to double check the calipers. Spent weeks playing around with mine on the 72. Got help but I was the only one that went under the car. Turned out the calipers were on the wrong sides but fit perfectly. Seem to recall the bleeder looked to be at the top (as I had read about it) but if you do have that wrong you'll never get'em to work. At work so no pictures available but worth a check.

First hand experience at this little issue :)

My bleeders are on the bottom on the calipers (close to the ground). You mean I have them on upside down; actually on the wrong sides? That could be my problem. I am using a DOT3 type brake fluid, um, I can't recall the brand but it is not Castrol but a standard US brand.

Thanks to all who have posted their responses, I really appreciate it.

Dean

As upside down as you can get......... Switch them side-to-side. You'll notice a significant difference in how they work after you bleed them.

Will do! :-)

Doesn't sound like this will apply, but in the interest of sharing information. . . on my 80 the master cylinder is divided into two sections. The opening to add the fluid is over the rearward section and it feeds the front brakes. The forward section feeds the rear brakes and if you are bleeding the rear brakes, it's easy to not notice that the front part of the MC has run out of fluid. You have to keep the back portion quite full, the fluid flows over the little divider between the sections and fills up the front section.

It took me quite a while to figure that one out when I changed the wheel cylinders and hoses. Once I actually got some fluid back in the system , it bled pretty easy.

mityvac!

Dean;
You did not say that you replaced the master cylinder. OH !! OH!! Say it aint so!!
Could be the problem.
Good luck. David

Two cheers for Mightyvac!

Thank you for your advice and your help on this. It seems that even with a left handed wrench, when the calipers are on the right way it works just as it should. I am back in business!

Thanks again, Dean