92 passenger front caliper locking up...i'm at my wits end (1 Viewer)

[LazyEye]

Hey Guys, (and Gals)

I'm at my wits end, I've searched and searched and troubleshot everything I can think of and I still can't track down what's causing my front right caliper to lock up at slow speed stops.

here's the skinny...
it never locks up at speed
never locks up when reversing
only clamps down when stopping at slow speed and not every time
when i apply the accelerator, it breaks free with a noticeable clunk then rolls freely
this is a non-ABS system

I've bled the system so many times from the drums and calipers and the lspv that I'm pretty sure I've replaced all the fluid by now.
I've attached the rod from the lspv to the top of the truck to prevent undue fluid being proportioned to the front because of my 2.5" lift
I've replaced the caliper with a reman unit
I've replaced the rubber axle to caliper line with an new line
I've put new quality pads in (both sides)
I've checked for crimped for dented hard lines and all are good
I've checked and double checked that my caliper bolts are nice and snugged down to spec

I don't know what else to do. It didn't do this when I bought the LC about 6-8? months ago, it only started about 2 months ago. I replaced the soft line about 4 months ago. I can't think of anything else. My birfs don't click, I've replaced my bearings on both sides.

I'm open to any and all suggestions, up to and including asking the gremlins who have taken up residence to kindly move on but I'm not sure what kind of peace offering they require.

I truly love this truck and even though I've owned toyota trucks for about 20 years now, this is the first one I've developed such an affinity for. I happily (and constantly) defend the mpg in discussions with my wife, after all the ability to go anywhere easily outweighs the 12mpg that I get. I'm committed to tracking this down, I'm just out of ideas about where to look next.

thanks ya'll

 

[inkpot]

Is the front left caliper puck sticking in the bore under light/slow braking, therefore all of the braking is being done by the right front caliper? When you brake harder at speed it is just enough additional pressure to move the sticky left puck?

 

[2fpower]

Soft lines or rusty, crusty calipers is what always the culprit for my locking issues.

Master is only $70 on Rock auto. Maybe try that?

 

[LazyEye]

Is the front left caliper puck sticking in the bore under light/slow braking, therefore all of the braking is being done by the right front caliper? When you brake harder at speed it is just enough additional pressure to move the sticky left puck?

I didn't consider that possibility, and now that you mention it, it makes perfect sense. I replaced the right caliper but not the left one. will replace the left asap and get back to the thread with the results.

the master cyl was replaced by PO before I bought it, and the brakes were functioning fine up until a couple of months ago. could be the left caliper is rusty/crusty or just a stuck piston.

 

[Jgunner]

I had a sticky caliper once, was deris in my hard line. Looked up in the hole and could see rust flakes. Replaced the hard line on that side, problem solved.

 

[LazyEye]

I had a sticky caliper once, was deris in my hard line. Looked up in the hole and could see rust flakes. Replaced the hard line on that side, problem solved.

it's worth a shot at this point. I'll replace the hard lines too at the same time if they aren't too crazy expensive.

 

[inkpot]

Well, you have covered most of the obvious solutions, so maybe ya gotta reach out for some of the less likely, but possible, solutions.

 

[LazyEye]

Well, you have covered most of the obvious solutions, so maybe ya gotta reach out for some of the less likely, but possible, solutions.

Agreed. Was hoping for some less likely but possible solutions. Will try what's been suggested thus far...still open for any more suggestions no matter how outlandish they may seem

 

[LazyEye]

got another quick question before i replace my drive side caliper and all the hard lines on the axle. when i replaced my passenger side axle to caliper soft brake line, i clamped it off with a pair of vicegrips to prevent brake fluid bleedout. i remembered doing that on my way home yesterday and wondered if the internal line could've become permanently squeezed because of my action in clamping it down. I don't know what the inside of those line look like or what they are constructed of.

anyone got any thoughts on this?

 

[jonheld]

Quick and easy brake line banjo plug
Pinching soft lines is a pretty bad idea.

 

[LazyEye]

Quick and easy brake line banjo plug
Pinching soft lines is a pretty bad idea.

Thanks for replying Jon. I'll just start by replacing that soft line then. OEM lines from my local Toyota house are 56 bucks each so I'm going to get a local hydraulics house to build me one...14 bucks, pretty big difference

And more importantly, it'll be a valuable lesson learned in not clamping off brake line to prevent leakage. Thanks for the link on the banjo plug, it's a good idea and I'm sure I've got what it takes to make one in my junk drawers

 

[jonheld]

Thanks for replying Jon. I'll just start by replacing that soft line then. OEM lines from my local Toyota house are 56 bucks each so I'm going to get a local hydraulics house to build me one...14 bucks, pretty big difference

And more importantly, it'll be a valuable lesson learned in not clamping off brake line to prevent leakage. Thanks for the link on the banjo plug, it's a good idea and I'm sure I've got what it takes to make one in my junk drawers

Personally, I wouldn't use anything but OEM parts on my brakes. There are several parts dealers on this forum that give good discounts or you can purchase OEM from one of the online dealers and have it shipped right to your door. Don't forget the 2 copper washers for each banjo fitting. Also note that OEM banjo fittings have locator pins to prevent them from spinning out of position when tightening the banjo bolt.

 

[LazyEye]

Personally, I wouldn't use anything but OEM parts on my brakes. There are several parts dealers on this forum that give good discounts or you can purchase OEM from one of the online dealers and have it shipped right to your door. Don't forget the 2 copper washers for each banjo fitting. Also note that OEM banjo fittings have locator pins to prevent them from spinning out of position when tightening the banjo bolt.

I have no problem going OEM as the budget allows but these guys at Hundley Hydraulics are the real deal. They custom build to virtually the same specs as OEM, right down to supplying the copper washers and the locator pin for the banjo fitting. This is what fits the budget right now, but I do understand your fondness for OEM, it's definitely usually the best option no matter what

 

[BILT4ME]

I have no problem going OEM as the budget allows but these guys at Hundley Hydraulics are the real deal. They custom build to virtually the same specs as OEM, right down to supplying the copper washers and the locator pin for the banjo fitting. This is what fits the budget right now, but I do understand your fondness for OEM, it's definitely usually the best option no matter what

Just for your reference.....
Toyota Parts | Toyota Online Parts | Genuine Toyota Parts | Toyota Parts Online

I can order from these guys and deliver to my door cheaper than I can drive across town and try to explain to my local dealer what I really need.
OEM parts are less than you might think.

 

[LazyEye]

Just for your reference.....
Toyota Parts | Toyota Online Parts | Genuine Toyota Parts | Toyota Parts Online

I can order from these guys and deliver to my door cheaper than I can drive across town and try to explain to my local dealer what I really need.
OEM parts are less than you might think.

I will check them out, thanks

 

[LazyEye]

to everyone who contributed ideas, thank you!

the solution ended up being very simple and the gremlin turned out to be one of my own making. i made a very noob mistake by clamping off the soft line a few months back on install so it wouldn't leak so much fluid, well that shouldn't ever be done for any reason. clamping the line damaged the internals and wouldn't let the brake fluid back flow after compressing the pistons, so a locked up caliper ensued. the only reason i didn't suspect that immediately was because that line was brand new and it didn't occur to me right away that i might have damaged it when i clamped it. of course it seems pretty obvious in hindsight...shout out to @jonheld for pointing out the obvious...something i should've figured out quickly but didn't

anyway, i ended up making a new hard line since the threads were buggered on one end, and no it's not as pretty as the factory bent line but it doesn't leak and the next one will be better. so one new hard line, one new soft line and my brakes are back! feels like I gained a little quicker acceleration too since the pads are no longer constantly dragging on the disk.