Notices
86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

yet another weird brake problem

Thread Tools
 
Search this Thread
 
Old Apr 27, 2010 | 04:00 PM
  #1  
buckz6319's Avatar
Thread Starter
Registered User
 
Joined: Jul 2008
Posts: 1,064
Likes: 2
From: GA
yet another weird brake problem

fixed

Last edited by buckz6319; May 20, 2010 at 04:56 PM.
Reply
Old Apr 27, 2010 | 04:09 PM
  #2  
desertcamper67's Avatar
Registered User
 
Joined: Dec 2008
Posts: 1,145
Likes: 0
From: San Diego
Are you sure your bearings aren't super sloppy?
Pads are kept snugly in place with all the hardware intact?
Everything got bolted down tightly after you did the brakes?
Reply
Old Apr 27, 2010 | 04:21 PM
  #3  
buckz6319's Avatar
Thread Starter
Registered User
 
Joined: Jul 2008
Posts: 1,064
Likes: 2
From: GA
................

Last edited by buckz6319; May 20, 2010 at 04:56 PM.
Reply
Old Apr 29, 2010 | 06:48 PM
  #4  
desertcamper67's Avatar
Registered User
 
Joined: Dec 2008
Posts: 1,145
Likes: 0
From: San Diego
Originally Posted by buckz6319
hell would that cause the pedal movement when turning the steering wheel while brake pedal depressed....IDK
I've seen lifted Chevy's with an aftermarket spindle that moved the calipers down to a spot where they actually hit the control arm or steering stops on turns. These were sliding calipers and they would actually compress the pistons during tighter turns. After they straightened up they had no pedal until it was pumped a couple of times.

This doesn't apply to yours most likely. I think you have 2 or 4 piston calipers that don't slide.
That's why I was thinking you had very loose bearings. A big movement from the rotor could compress your piston(s) in a caliper and a loose hub could move more upon steering.
Reply
Old Apr 29, 2010 | 07:02 PM
  #5  
yayfortrees's Avatar
Registered User
 
Joined: Mar 2010
Posts: 485
Likes: 0
From: SE Kansas
The loose bearings are about the only thing that makes sense to me. It also sounds like your calipers are sticking.

Since the master cyl. is new, that should be fine, but to test the cylinder vs. the calipers, you can raise one of the front tires off the ground. Crack the bleeder loose, and see if that wheel loosens up any. If it does, you know the master is holding pressure for some reason, or you have a collapsed / pinched brake line.

I've seen this happen only a couple of times (the collapsed brake line), and they were on GM trucks both times. The line collapsed internally, pressure could get past when the brake was applied, but then the line would hold some pressure once release, sticking the caliper somewhat.

The rest of your problem sounds very strange indeed. Definately keep us posted on your findings.
Reply
Old Apr 29, 2010 | 09:30 PM
  #6  
betelnut's Avatar
Registered User
 
Joined: Dec 2009
Posts: 268
Likes: 0
From: Austin, TX
Also shooting in the dark here, but there's an 'idle up device' (check FSM p. SR-26, Power Steering Description section) that increases the idle a little while you're turning the wheel in order to supply the P/S pump with a little extra power.

This could affect the brakes, which are powered by manifold vacuum, which in turn varies depending on engine speed.

Try to listen to engine RPMs and see whether there's a change at the same time the brakes do their funky thing.
Reply
Old Apr 29, 2010 | 11:49 PM
  #7  
hunter4runner's Avatar
Registered User
 
Joined: Jan 2010
Posts: 208
Likes: 1
From: Statesboro or Loganville, GA
you have rear anti-lock?
and when you turn the wheel the pressure in the pedal is increased?

if this is the case it is due to the fact that the power steering boosts the brakes, this is called "hydro-boost" or "hydro-assit" and is a system found in many heavy duty chevys, well how do you stop it ? well two things to minimize its side effects

1) bleed the crap out of the brakes all of them uses the fsm for correct procedure
2) bleed the power steering per the procedure in the fsm

that should solve the issue
Reply
Old Apr 30, 2010 | 02:19 AM
  #8  
buckz6319's Avatar
Thread Starter
Registered User
 
Joined: Jul 2008
Posts: 1,064
Likes: 2
From: GA
..........

Last edited by buckz6319; May 20, 2010 at 04:57 PM.
Reply
Old Apr 30, 2010 | 09:02 AM
  #9  
yayfortrees's Avatar
Registered User
 
Joined: Mar 2010
Posts: 485
Likes: 0
From: SE Kansas
Originally Posted by hunter4runner
if this is the case it is due to the fact that the power steering boosts the brakes, this is called "hydro-boost" or "hydro-assit" and is a system found in many heavy duty chevys,
Huh, I've never heard of this, but then again I don't pay much attention to GM stuff. Are you sure 4Runners have this? Is the brake booster not enough?

I do second the notion to bleed the brakes again, following the FSM procedure.
Reply
Old Apr 30, 2010 | 11:56 AM
  #10  
buckz6319's Avatar
Thread Starter
Registered User
 
Joined: Jul 2008
Posts: 1,064
Likes: 2
From: GA
..............

Last edited by buckz6319; May 20, 2010 at 04:57 PM.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Eggslinger
86-95 Trucks & 4Runners
22
Jun 8, 2019 03:32 PM
icentropy
86-95 Trucks & 4Runners
7
Jul 14, 2015 10:23 AM
Johntom240
General Electrical & Lighting Related Topics
7
Jul 13, 2015 12:18 AM
jon.r
General Vehicle Related Topics (Non Year Related)
8
Jul 11, 2015 03:34 PM
Jnkml
95.5-2004 Tacomas & 96-2002 4Runners
3
Jul 6, 2015 01:20 PM




All times are GMT -8. The time now is 08:32 PM.