Rear Brake Job - Cleaning/Adjusting LSPV? - Toyota Nation Forum : Toyota Car and Truck Forums


» Auto Insurance
» Featured Product
Advertisement
Wheel & Tire Center

Go Back   Toyota Nation Forum : Toyota Car and Truck Forums > Toyota Truck, SUV and Van Forums > Hilux (Pickup) Forum > Pre-88 Toyota Pickup/Hilux

Pre-88 Toyota Pickup/Hilux Discussion area for the '88 and older Toyota Pickup/Hilux. NEW!

ToyotaNation.com is the premier Toyota Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 11-23-2010, 01:30 AM   #1 (permalink)
Official TN Member
 
Join Date: Dec 2004
Location: Washington
Posts: 262
Thanks: 0
Thanked 2 Times in 2 Posts
iTrader Score: 0 reviews
View 87_SR5's Photo Gallery
Rear Brake Job - Cleaning/Adjusting LSPV?

'87 Pickup 4x4 SR5

Well I am getting tired of it. My rear end locks up way to easy, and I suspect its the LSPV. It only seems to do it when it is wet outside, which is weird, but I read someone else had the same problem. With winter already here, I'd feel safer with it working properly if I get into some snow. Why did I wait until now to fix it?

Anyways, I am going to do the full job, rear pads and possibly drums too (if I can't get them turned). I was thinking of flushing my entire brake system too..

Am I able to clean my LSPV? Does it come apart easily and are their parts to replace inside of it? Any information on this would be great! I know they are expensive, so I hope a cleaning will fix it.

How do I go about adjusting the LSPV? I read through the FSM, but their method was not simple at all.

Thanks!

Last edited by 87_SR5; 11-23-2010 at 01:40 AM.
87_SR5 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 11-23-2010, 07:13 AM   #2 (permalink)
Official TN Member
 
Join Date: Aug 2007
Location: Garner NC
Posts: 536
Gameroom cash: $131415
Thanks: 1
Thanked 36 Times in 36 Posts
iTrader Score: 0 reviews
View Rh1n0_86OneTon's Photo Gallery
Shouldn't need to disassemble the LSPV. There are no rebuild kits for them. How it works is the more weight in the bed, the more assist it gets from the front brake circuit. If the pin is stuck at a compressed position you will have the symptoms you describe. The pin just rides on the actuator rod so grab the end of it and pull it down. Most people just bypass the LSPV because it can cause problems like you have. I actually added one to my truck as part of my 1 Ton conversion because it will be helpful when I have a ton of gravel in the bed. There are plenty of threads on bypassing the LSPV.
Rh1n0_86OneTon is offline   Reply With Quote Quick reply to this message
Old 11-23-2010, 10:42 AM   #3 (permalink)
Official TN Member
 
Join Date: Dec 2004
Location: Washington
Posts: 262
Thanks: 0
Thanked 2 Times in 2 Posts
iTrader Score: 0 reviews
View 87_SR5's Photo Gallery
Thanks for the reply. Would it be worth removing the LSVP and cleaning it? Maybe it is gummed up?

I will look into bypassing it. That might be an option.

Any theories on why I only really notice it when its damp/wet outside? I haven't actually had the tires lock up and slide on me, but I can definitely tell when the back brakes grab A LOT more than the front. I've never noticed it when its dry out...the reason why I never really thought of it during the summer.

As far as adjusting the LSVP, is it kind of a trial and error thing? Or is there a method do doing it?
87_SR5 is offline   Reply With Quote Quick reply to this message
Old 11-23-2010, 01:49 PM   #4 (permalink)
Soylent Green sales
 
fourwd1's Avatar
 
Join Date: Jul 2006
Location: the Socialist State of Maryland
Posts: 8,104
Gameroom cash: $872855
Thanks: 5
Thanked 457 Times in 439 Posts
Lifetime Supreme Member
iTrader Score: 1 reviews
View fourwd1's Photo Gallery
If you can bleed the LSPV, it should be working OK.
It shouldn't need adjusting, unless

You have a suspension lift, but they usually come with an extension bracket to address it.
or
Your springs are worn bad and the back of the truck is sitting real low, the LSPV would interpret that as a heavy load and allow more braking power to the rear.

Bypassing or eliminating the LSPV would provide max brake fluid to the rear. Disconnecting it at the axle and tying the rod up tight to the frame would do the same thing.
__________________
SEARCH before asking
84 4Runner rockcrawler - ARBed 5.29's, 36" TSLs, dual t-cases w/ 4.7 crawler gear, Chevys, 30 spline Marlins
83 p/u trail rig - Buick 231 V6, Weiand intake, Holley 4 bbl, TH-350 auto w/700R4 low gearset, dual tanks ...
89 4Runner - stock
http://www.cardomain.com/id/fourwd1
fourwd1 is offline   Reply With Quote Quick reply to this message
Old 11-23-2010, 05:33 PM   #5 (permalink)
Official TN Member
 
Join Date: Dec 2004
Location: Washington
Posts: 262
Thanks: 0
Thanked 2 Times in 2 Posts
iTrader Score: 0 reviews
View 87_SR5's Photo Gallery
Great info!

I do not have a suspension lift. Everything is stock. I don't know if the spring is sitting low or not...looks normal to me.

We had the rear end rebuilt by a shop that I was not impressed with...this was 5+ years ago. Shortly after we got the truck back one of the rear brake cylinders was leaking...some idiot put the seal in backwards. Also, the rear end still felt sloppy (backlash), right from the shop. Anyways, that is besides the point. My point is I wouldn't be surprised if they messed up the LSPV adjustment, or didn't know you were suppose to bleed the LSVP. The brake shoes have been changed since then, but I have never bled the LSPV.

I think I remember reading about guys putting in their own, manual PV...while bypassing the original LSPV (if the LSPV turned out to be shot).

Why would someone want to eliminate the LSPV w/o putting in aother PV? Like you said, it would provide full braking to the rear...which is the problem I am trying to eliminate. Don't you want something like 60/40 braking (front/rear)?
87_SR5 is offline   Reply With Quote Quick reply to this message
Old 11-24-2010, 09:01 AM   #6 (permalink)
Official TN Member
 
Join Date: Aug 2007
Location: Garner NC
Posts: 536
Gameroom cash: $131415
Thanks: 1
Thanked 36 Times in 36 Posts
iTrader Score: 0 reviews
View Rh1n0_86OneTon's Photo Gallery
http://personal.utulsa.edu/~nathan-b...12loadsens.pdf
http://www.4x4spot.com/proportioning.htm

The front and rear brakes are tied together through the LSPV-BV. The only reason to do this versus just an adjustable prop valve is to redistribute fluid force from both systems in the event of braking under various loads. So a portion of the front wheel braking force is transferred to the rear. Picture the LSPV as a proportioning valve and a summation valve. Eliminating the front brake contribution (bypassing) does not make for maximum rear braking; it makes for standard rear braking. My 2WD did not come with an LSPV. I put one in. Granted I have yet to get all up in the binders under heavy load, but I don't drive like a maniac at all let alone with a ton of rock in the bed. The above articles talk about adjustment and bypassing respectively. Somewhere in my bit bucket I have a pdf from Toyota explaining the actual function of the LSPV-BV. I'll see if I can dig that out.
Rh1n0_86OneTon is offline   Reply With Quote Quick reply to this message
Old 11-24-2010, 09:23 AM   #7 (permalink)
Official TN Member
 
Join Date: Aug 2007
Location: Garner NC
Posts: 536
Gameroom cash: $131415
Thanks: 1
Thanked 36 Times in 36 Posts
iTrader Score: 0 reviews
View Rh1n0_86OneTon's Photo Gallery
Found it on line. It's a good read all the same.

http://www.autoshop101.com/forms/brake08.pdf
Rh1n0_86OneTon is offline   Reply With Quote Quick reply to this message
Old 11-24-2010, 10:09 PM   #8 (permalink)
Official TN Member
 
Join Date: Dec 2004
Location: Washington
Posts: 262
Thanks: 0
Thanked 2 Times in 2 Posts
iTrader Score: 0 reviews
View 87_SR5's Photo Gallery
Thanks for the info! Definitely saving that for future reference
87_SR5 is offline   Reply With Quote Quick reply to this message
Old 12-04-2010, 06:30 PM   #9 (permalink)
Official TN Member
 
Join Date: Dec 2004
Location: Washington
Posts: 262
Thanks: 0
Thanked 2 Times in 2 Posts
iTrader Score: 0 reviews
View 87_SR5's Photo Gallery
I had to work on the other rig today, but I managed to climb under my Toyota and have a look. I think I found my problem:




The LSPV is in the fully UP position! Not good! It has been like that for years too...like I said before I don't know if the shop that rebuilt the rear-end did it, or it has been like that since we bought the truck.

So now my question is, how can I adjust the LSPV without having any of the pressure gauges that are used in the FSM?

EDIT: I was thinking, does anyone know the stock distance between the bump stops and the stops? You can see in the picture mine are pretty close and I am beginning to think my leaf springs are sagging. With almost 190,000 miles, I wouldn't doubt it. That would explain the LSVP being out of adjustment...

Last edited by 87_SR5; 12-05-2010 at 06:38 PM.
87_SR5 is offline   Reply With Quote Quick reply to this message
Old 01-15-2011, 11:33 PM   #10 (permalink)
New TN User
 
Join Date: Jan 2011
Location: Washington
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
View brewdogg's Photo Gallery
Update

So where you able to fix the problem? If so what did you do to remidy the situation? I have a similar problem so I was wondering what worked for you.
brewdogg is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

  Toyota Nation Forum : Toyota Car and Truck Forums > Toyota Truck, SUV and Van Forums > Hilux (Pickup) Forum > Pre-88 Toyota Pickup/Hilux

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Toyota Nation Forum : Toyota Car and Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 06:18 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
ToyotaNation.com is an independent Toyota/Lexus enthusiast website. ToyotaNation.com is not sponsored by or in any way affiliated with Toyota Motor Sales, USA, Inc. The Toyota, Lexus and Scion names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.