[Spridgets] Help - Seemingly Incurable Brake Fade

[Peter Caldwell]

What Dean says.

         You said "fade". That's when brakes overheat and become less 
effective in a single stopping action.

Having to pump the pedal to get brakes can have several causes.... 
mechanical and/or hydraulic

Hydraulic.... as you know, air in the system. Having even a small 
weep can cause this. Fix that, especially if it is at a fitting.

Mechanical..... Brake pistons (caliper or wheel cylinder) can only 
move very little. The pads or shoes must be set so they are very 
close to the disc or drum.
         Disc.. no adjustment BUT, if there is play in the wheel 
bearings, or hub or the disc is warped, the resulting wobble 
(run-out) will push the pistons in farther than they can be pushed 
out in a single pedal pump.
         Drum...shoes must be adjusted to be close to the drums. 
There are return springs that retract the shoes, and hence the 
pistons as far as permitted by the adjusters. You should have no more 
than 4 clicks on the handbrake lever. To test this, fully engage the 
handbrake, and feel if the pedal is different. Unlike discs, shoes 
wont retract during rotation. (unless the drums are horribly wonky)
         The several quick pumps "catches" the shoes/cylinders before 
they've had time to fully retract.

         Double check that stuff. It's ONLY brakes.
Peter C.
=====
At 06:48 PM 10/2/2009, Dean Hedin wrote:
>When you converted the brakes over to disc, did you also convert the 
>rear brakes to the later double acting pistons?
>
>One thing you can do to help isolate the issue is to disconnect the 
>line going to the rear from the junction block
>and put a bolt in it's place.  If the pedal firms up then you will know
>that the rear brakes are the culprit.
>
>Make sure the rear brake adjusters are not loose when you bleed the 
>rear brakes.
>
>
>----- Original Message ----- From: "Kirk Hargreaves" <khargreaves2 at gmail.com>
>
>>59 Bugeye 1275. .  disk brake conversion from a latter year Sprite.
>>I have bled the master cyl, the slave cyl and all the wheels beginning at
>>the passenger side rear wheel and working to the driver side rear, then to
>>the passenger side front, and the driver side front.
>>All bled out. .  still get brake fade. . it still feels like I am still
>>pushing air through the brake lines when I pump the brakes to stop.