Brake VENTING, "literally" Options

[aveale]

First of all, I would like to thank everyone for helping me get to where I am now!! (Engine out, longs done, engine in, fuel pump stuff, pushrod seals, valve adjustments, engine running......)

Because I messed with things (i.e. it was not broken, buy I tried to make things better and they are now worse! (IMG:http://www.914world.com/bbs2/html/emoticons/icon8.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif) ) 3 Questions for the brake guys!

1- i have searched this site and found a good clearance is half of what the Haynes says (right now, it is at the Haynes value). Will this make a big difference?

2- my brakes need to pump up 1-2X to get effective stopping - is that acceptable (this may be related to #1)?

3- I can't seem to reduce the clearance on my rear-passenger side caliper. I have done the drivers side with no problem but on this one the allen key will spin without changing anything (this may be the cause of #2). Is this a repairable problem OR do I have to spend more $$$ on a new caliper??

Thanx

T

[qa1142]

if you are pumping it is likely air in the lines. try bleeding (the lines (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) )

[Allan]

QUOTE (qa1142 @ Sep 18 2005, 05:35 PM)

if you are pumping it is likely air in the lines. try bleeding (the lines (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) )

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) Try bleeding them again. Right rear, left rear. right front, left front, etc...

Not too sure about the venting clearance. Maybe a stripped adjuster?

[Dr. Roger]

might it also be your rear rotor is out of spec. thickness is? or brake pads worn too much? causes the cliper to "reach" too far. this would also explain the running-out of adjustment.

i like the vent adjustment fix the best if they are in spec IMHO.
then get some hard sticky pads. =-)

i followed your progress thread and really appreciated your swift and consistent work u put into that thing. great work. =-) (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

[Joe Bob]

Air in the lines and prolly crappy fluid. When was the fluid last changed? Was it during the Nixon or the Carter administration? (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Pull the cailpers rebuild them and replace the fluid with GOOD stuff, like ATE Blue.

[markb]

Don't forget the adjusters turn opposite of each other. One adjusts clockwise, one counter-clockwise.

[Eric_Shea]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) The inner adjuster turns the opposite of what you'd expect (it's gear driven... that's why).

To Tighten or move the pads toward the rotor:

The inner adjuster turns clockwise.
The outer adjuster turns counter clockwise.

If you keep turning the adjuster but get no movement then your piston is probably rusted to the edge of the bore. It happens when you get a bad dust seal and water gets in. Also... you're inner adjuster machanism has a small spring on it. It has now probably come out of its retaining hole (its been cranked too many times/wound up too tight and it snaps out). You'll need to remove the piston and fix the spring (PM me, I have some tips). The inner mechanism may have to come out. Early ones were attached at the bottom of the assembly/piston and later ones were at the top and easier to get at. If it's a 72-76 car you may be in luck.

Your other woes are probably a P-Valve that needs bleeding. Keep bleeding.

E.

[aveale]

I hate bleeding brakes!

Thanx so far!


Does anyone else have to pump things(1X) to make car stop REALLY FAST compared to not pumping (read--RELATIVLEY SLOW)?

My theory is that my venting clearance is too large on one side, so the system needs to be pumped to close off this distance. Any thoughts?

Thanx family!

T

[rhodyguy]

speed bleeders. NEVER look back.

k

[Mark Henry]

On the P-valve... cracking the lines and give a pump (with a buddy), sometimes that will clear the air in the line.

[Eric_Shea]

QUOTE

My theory is that my venting clearance is too large on one side, so the system needs to be pumped to close off this distance. Any thoughts?

I doubt it but you need to fix that for sure.

1. Make sure you "can" adjust the pad clearance. Set it at .004 not .008.
2. If you can, move on to 2a. If you can't, rebuild it, get a new one, etc.
2a. Bleed, bleed, then bleed some more. These "are" tricky animals to bleed. Either bleed the p-valve or have an assistant pound on the pedal hard a few times.
3. Set the venting clearance with the handbrake cables off. Check for an uneven rotor.
4. Once you have it bled. Bleed it some more! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Dr. Roger]

QUOTE (Eric_Shea @ Sep 19 2005, 10:07 AM)

[QUOTE] 3. Set the venting clearance with the handbrake cables off. 4. Once you have it bled. Bleed it some more! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

Ahhhhh! Yes!

Sounds like somethig I might do.. Thanks. =-)

(IMG:http://www.914world.com/bbs2/html/emoticons/blink.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Trekkor]

QUOTE

speed bleeders. NEVER look back.

The best.

Also, regardless of what the naysayers post, bleed the lowers, too. Do all eight bleeders, lowers first on each caliper.

With Speedbleeders it's a 10 minute job if the wheels are off and you have an assistant.
15 minutes, solo...

KT