YotaTech Forums  

Go Back   YotaTech Forums > Toyota SUV & Truck Tech > 84-85 Trucks & 4Runners
Sign in using an external account
Register Forgot Password?
Search


84-85 Trucks & 4Runners 2nd gen pickups and 1st gen 4Runners with solid front axles

Welcome to Yotatech!
Welcome to Yotatech,

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!


Reply
 
LinkBack Thread Tools Search this Thread
Old 08-14-2011, 09:14 AM   #1 (permalink)
Registered User
Personal Sales Rating: (0)
 
84yotaman's Avatar
 
Join Date: Apr 2009
Posts: 17
Front brakes keep locking up help!!!

i was driving down the freeway and both of my front brakes locked up not completely but noticeable as soon as i relief the pressure it was fine for like thirty minutes then they just locked up again and i know its not the pistons in the caliper because its both sides doing it im leaning more toward master cylinder or lspv (load sensioning porportioning valve) but where is the lspv located? or does anybody know whats going on.. oh and when they lock up the petal is really stiff...
This ad is not displayed to registered members.
Register your free account today and become a member on Yotatech!
84yotaman is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-14-2011, 05:25 PM   #2 (permalink)
Registered User
Personal Sales Rating: (0)
 
fourtrax's Avatar
 
Join Date: Jul 2006
Location: Raleigh, NC
Posts: 24
lspv is mounted above the rear axle, drivers side, and has a rod (that looks sighlty bent) that runs down to the rear axle. i doubt the lspv is causing your front brakes to lock up. However if you have checked out the front calipers and find they are in good working order then you might look at the one way vacuum "check vlave" that is against the firewall between the engine and the brake booster, as it could be bad. next time it locks up temparlary remove the vacuum line from the brake booster and see if the brakes unlock.

the check valve part number is 44730 in the picture below
http://www.autoconnectioninc.net/DaC...e.php?pID=6517
__________________
1994' Toyota Landcruiser FZJ80

Last edited by fourtrax; 08-14-2011 at 05:32 PM.
fourtrax is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-15-2011, 07:00 AM   #3 (permalink)
Registered User
Personal Sales Rating: (0)
 
evileyejones's Avatar
 
Join Date: Feb 2011
Location: Dfw metroplex
Posts: 115
Evileyejones Evileyetreece
I once had a "friend" top off what he thought was his powersteering reservoir (in a corolla) with fluid, but it was actually his brake fluid reservoir.

whenever my "friend" would drive for about half an hour to an hour, the brakes would start to grip on their own, and eventually would lock up. relieving pressure by taking off the cap, and letting it cool down remedied it till about 15-30 minutes of driving again.

turned out that brake fluid does not expand that much when heated, whereas most other fluid does. so when the fluid that was not brake fluid, but was in the break system heated up, it acted as iff someone was slowly pushing on the break, till it was all the way engaged.

the remedy was to drain the brakes system, and flush all the metal lines, and replace the non metal lines. (shop estimated $1300, I did it in my garage for about $80, which includes one of those hand pumps, new fluid, and the stuff to flush with, I want to say it was denaturalized alcohol or something like that.)
__________________
current:
1987 "sr5" 4runner 22re manual

My brothers:
1986 4runner, 22re auto

My dads:
1988 pickup, 22re manual currently not working,
bad compression, will replace shortblock when weather warms up.

Previous:
1989 Sr5 4runner 6cyl fully loaded
1989 4runner 6cyl
evileyejones is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-15-2011, 10:42 AM   #4 (permalink)
Registered User
Personal Sales Rating: (0)
Threadstarter [OP]
 
84yotaman's Avatar
 
Join Date: Apr 2009
Posts: 17
thanks guys i will check it out i bought a new master cylinder and putting it on today i will let you guys know what happens
84yotaman is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-24-2011, 03:44 AM   #5 (permalink)
Registered User
Personal Sales Rating: (0)
 
uijongbu87's Avatar
 
Join Date: Feb 2011
Location: Sellersburg, IN
Posts: 53
I am having this exact same issue, Let me know what you came up with as a solution. Just started yesterday! very strange!
uijongbu87 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-24-2011, 06:45 AM   #6 (permalink)
Registered User
Personal Sales Rating: (0)
 
Shoua's Avatar
 
Join Date: Apr 2007
Location: Yuba City, CA
Posts: 544
It could be something as simple as the brake lines. They may have swollen too much to the point where the fluid will only go one way and not the other. Happened to me before.
Shoua is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-24-2011, 08:21 AM   #7 (permalink)
Registered User
Personal Sales Rating: (0)
 
uijongbu87's Avatar
 
Join Date: Feb 2011
Location: Sellersburg, IN
Posts: 53
I noticed that after you let the truck sit for a while and let everything cool down. It runs fine. My pedal is super stiff when they stick too. I am gonna check that check valve and see if it is defective.
uijongbu87 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-25-2011, 02:59 AM   #8 (permalink)
Registered User
Personal Sales Rating: (0)
 
uijongbu87's Avatar
 
Join Date: Feb 2011
Location: Sellersburg, IN
Posts: 53
Checked the vacuum check valve and that wasn't broken. Could be my master cylinder.... Don't know what to check really. Going to do some more research and see what I come up with before I start buying anything.
uijongbu87 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-25-2011, 06:44 AM   #9 (permalink)
Registered User
Personal Sales Rating: (0)
 
Shoua's Avatar
 
Join Date: Apr 2007
Location: Yuba City, CA
Posts: 544
Quote:
Originally Posted by uijongbu87 View Post
Checked the vacuum check valve and that wasn't broken. Could be my master cylinder.... Don't know what to check really. Going to do some more research and see what I come up with before I start buying anything.
Check your brake lines!

If they're old and start swelling, it could be letting fluid go one way fluidly but SLOWLY returning back. That might explain why after letting it sit for a while, it'd be okay. Plus, when you're driving, it's creating heat in the brake fluid which would cause things to expand.
Shoua is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-26-2011, 08:05 AM   #10 (permalink)
Registered User
Personal Sales Rating: (0)
 
uijongbu87's Avatar
 
Join Date: Feb 2011
Location: Sellersburg, IN
Posts: 53
Ok going with Shouas' advice. Gonig to get a new set of brake lines. Fluid comes out, but that doesn't mean a whole lot about fluid freely flowing back to the MC.
So got a set of extended stainless brake lines.
Also, while I am at it, i bought a brand new MC. This should take care of the issue. Lines will be here wed. I will post what the outcome is.
uijongbu87 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 08-26-2011, 12:28 PM   #11 (permalink)
Registered User
Personal Sales Rating: (0)
Threadstarter [OP]
 
84yotaman's Avatar
 
Join Date: Apr 2009
Posts: 17
well i put new master cylinder on it but still doing it i have no idea
84yotaman is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 09-03-2011, 05:18 AM   #12 (permalink)
Registered User
Personal Sales Rating: (0)
 
uijongbu87's Avatar
 
Join Date: Feb 2011
Location: Sellersburg, IN
Posts: 53
Update, I replaced my brake lines and the master cylinder and don't seem to be having the Problem anymore. Although I do know what the problem was. When I changed out the parts, i put in new brake fluid. My old fluid was mostly water. And being right by the exhaust manifold, the fluid would expand, locking up only that wheel...
uijongbu87 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 09-24-2012, 04:05 PM   #13 (permalink)
Registered User
Personal Sales Rating: (0)
 
Join Date: Sep 2012
Posts: 1
I just had the same thing happen not more than 1/2 hr ago. I was only 1/2 mile from home so I just opened the bleeder valves on the front brakes (one at a time) while my friend put pressure on the brake pedal. Worked good enough to get me to the house.

I noticed evileyejones comment about putting ATF instead of brake fluid in the resevoir. Guess what, I stuck my finger down in the resevoir and found that the fluid was red. Looks like my mechanic has some "SPLAININ" to do, as Ricky Ricardo used to say. Thanks for that one evil eye.
justjoe is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 09-24-2012, 04:59 PM   #14 (permalink)
Registered User
Personal Sales Rating: (1)
 
rokblok's Avatar
 
Join Date: Feb 2011
Location: The Dirty South
Posts: 1,824
Brakes gaining pressure after driving is almost always fluid contamination/condition. As was stated, bad fluid will heat up, expand and apply pressure to the calipers/wheel cylinders. That's whys its important to change/flush the brake fluid every couple years to keep things working right.

I do mine yearly regardless if it needs it or not. And always use good quality fluid.... I prefer just good old Wagner brand, not parts house brand. No need for synthetics or DOT 100 racing silicone super fluid. Just keep it clean and fresh and you'll be good.
__________________
84 x-tra cab, 4X4, 4" TG rear springs installed by WabFab, TG extended shackles, Bilstein shocks, 315-75R16 Toyo Open Country MT on 16x8 Mickey Thompson Classic III Black, 3RZ powerplant w/ LCE Performance Master rebuild kit, 6-shooter knuckles, Hy-steer, blah, blah, blah.... And a Softopper, and.....ARB front bumper, big brake upgrade up front, IFS rear, W56B trans, Marlin 1200lb clutch...

1988 4Runner 3.0(hole in the block), 5-spd

1971 FJ40 all stock...in storage...
rokblok is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Old 09-24-2012, 04:59 PM
Yotatech
4WD Truck




Paid Advertisement
Reply

Tags
1985, 4runner, 85, brake, brakes, braks, completly, drive, front, load, lock, locked, locking, sides, toyota, up

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -8. The time now is 12:02 AM.


2010 InternetBrands, Inc.

Search Engine Friendly URLs by vBSEO 3.5.2