Front left lock up

[Casper34]

I have read that people have the rears lock up, but my front left locks up. I do have RABS and I have replaced the caliper, pads, rotor, hoses (left and right). The bearings seemed to be fine, packed full of grease. This only happens cold, when driving a long distance without hitting the brakes, or if I pump them. After I stop its fine till the next time I try to get it to do it or long trip. I still have the original master.

History:

Dropped 2-3 (flipped the rear with no shackles, so a 5 drop there and cut 1 coil out of the 2in drop springs)

Parked for close to 6 years (syncro issue, no oil)

Before it was parked, I would go through front brakes every 2-3 months

Have replaced both hoses (l and r) from dealer and aftermarket, replaced both calipers (aftermarket god knows how many times)

99 ranger, 3.0, RABS, I call it a 4-5 drop (no notch), 15in American Racing wheels


I am lost here. The hoses are not twisted or kinked. I have tried DOT 5 and 3 fluids, bled the system. Does someone had any clues, other then its "normal" for a ranger to do this? I work in a auto shop ad have driving many others that don't do this. Wheels should not lock up under normal braking.

Sent from my Ktweaked PACmaned SGS3!

 

[HAPPY+RANGER+GUY]

Is it possible the slider pins aren't getting lubed up real good or perhaps using a product that isn't cutting the mustard?

Another thought would be the piston overextending for some reason and binding up that way?

Strange but the slider pins certainly come into question and you've replaced them along with the caliper I assume?

T.

 

[HAPPY+RANGER+GUY]

Pins

Go to the 2:55 mark in this video to see what I'm talking about.

http://www.youtube.com/watch?v=xbs9mE6D6VM


T.

 

[Casper34]

Go to the 2:55 mark in this video to see what I'm talking about.

http://www.youtube.com/watch?v=xbs9mE6D6VM


T.

Its not the sliders either. Sorry. I keep thinking it the master and since the FL is closest to the master it locks first and I let off before the FR locks.

Sent from my Ktweaked PACmaned SGS3!

 

[HAPPY+RANGER+GUY]

Certainly could be that master. How is the condition of your fluid?

 

[RonD]

Well master problem would cause both front brakes to lock up assuming you have equal pressure at both, equal pressure is the point of hydraulics in braking systems.
So shorter line/longer line shouldn't matter.

If pressure to FR is limited the FL would tend to lock up, so issue could be on the opposite wheels system.
Could even be the atmospheric pressure valve in the power booster, this is on the firewall side of the booster, when your foot is on the pedal this valve opens a little to allow some of the 15psi sea level air pressure in to the booster, this is the "power assist", if valve is opening too much then brakes are applied more so system seems "touchy".

If both calipers are new then I would trace the lines back to the splitter or Rear ABS valve.
The RABS is in essence the Ranger version of a proportioning valve, or they have a "rear brake limiter" on the master cylinder.
But the two front brake lines meet somewhere, find that fitting and check it.

 

[cvar]

Locking up is not normal. Mine don't lock up, ever.

The rear brake line doesn't affect the front, so I'd ignore the RABS line.
Only 1 hydraulic line goes from MC to LF brake hose. Atop that LF hose is the only splitter block that divides fluid between LF and RF. Hmm, if you swap its 2 input fittings, does the RF lock up instead of LF? I'll bet not. Cuz I'll bet it has nothing to do with fluid, since only 1 of 4 wheels lock up.

My guess:
If the LF caliper or pads are not releasing, then I think your metal parts are binding. Either the caliper pistons are rusty inside, or the slider pins need polishing & grease, or the caliper slider shims are rusty (or missing) & need polishing & grease. Same for the little slider shims at top & bottom tabs of brake pads. All of those need to slide freely.

Lastly, perhaps 1 of your pads don't quite fit? On a recent set of brand new Wagner brake pads, the 1" wide tab on 1 pad didn't quite fit without forcing it into place. So I had to grind off almost 1/16 inch from the top tab, to make it fit & slide properly. Poor quality control.

See photos: http://imgur.com/a/URjHr

Hope you find it soon.

BTW, what I call "shims" are also known as anti-rattle clips.

 

[Casper34]

Ok... fluid is fine. The calipers, hoses, and fluid was 100% replaced when I got the truck back on the road, about 4 months ago. All the hardware was replaced on the calipers. Shims, guide pins, and the caliper spring. I was shocked that when I got the calipers that it came with all new hardware, so I used it all, lol. Used the black synthetic caliper grease on the shims on the pads and on the pins.

Also, just noticed on my trip home tonight, that it did not do it. The truck was parked for 2 days and it didn't do it.

I do.... don't think it should matter, have a cam installed. Could the cam, against all other cams, be creating to much vacuum? I will try to pay attention more to the way the truck idles when it does it.

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