Yet another LSPV adjustment Q

[latinoguy]

Well Today I replaced the rear brake pads and rear rotors in addition to bleeding the brakes.

I want to adjust the LSPV but there are dozen of threads where different people have done different things and some with mixed results.

I have J springs in the front and heavy's in the rear.

Some popular mods have been:
Landtanks 1/2" tubing home depot mod...
Hayes referencing Slee's website on adjustments...
Beowolf says the same on even an older thread on adjusting the LSPV about 1/2" on the bracket.... Is the consensus still 16:1 ratio of movement?

How should I adjust the LSPV to compensate for the j fronts/heavy rear springs? too much information out there....

 

[AKcruiserfreak]

x2 on this. I have the same lift and am wondering how much to compensate. A few days ago sombody else had a cool approach to the mod as well.

TK

 

[UCBerzerkeley]

-B- will not be pleased when he finds this thread

 

[UCBerzerkeley]

How should I adjust the LSPV to compensate for the j fronts/heavy rear springs? too much information out there....

Why make it lift specific? Or if it has to be a lift specific protocol, how about a method for J/Heavy/Medium categories? If this thread doesn't try to encapsulate all the info for each lift, it will fall by the wayside just like the threads you researched

 

[M23TLC]

Like a lot of things, I trust seat of the pants testing better than adjusting to meet a certain spec. Play around with the LSPV and leave it where you like.

 

[jfz80]

At that height i think you will be fine adjusting 1/2'' at the LSPV bracket. With the weight your sigline suggests you should not have more than 2.5'' of lift so you should be within adjustment range at the bracket. When you get into more lift(or bracket is rusted/immobile), I think it gets more involved and has been solved w/ adjusting at the shackle/axle end either by Landtanks method or the FSM/Lscool method.
Welcome to Land Cruiser Owners On Line
Just make sure your control arm isnt bending the hardline to LSPV under full flex.

 

[Tapage]

IMOP there is no magic rule on it .. coz all trucks are different and get different height with same coils .. I just more it after my lift and take my Cruiser for a ride .. then adjust until I feel it's braking balanced front and rear ..

Thought I move mine about 1" down ...

 

[mikedamageinc]

I tried the seat of the pants adjustment and when it felt tight, the rear pads went metal to metal in no time. Is the brake pressure tool something that can be rented or borrowed from the "loan a tool" places, or can the dealer do a proper adjustment for a reasonable fee? (yes I realize the humor of "a reasonable fee")

 

[latinoguy]

I wouldn't be able to do a seat of the pants adjustment myself because I don't have a good clue as to what to look for or how to test it?

 

[Atoyot1031]

latinoguy,
IMHO the best actual test is as follows (and requires two people to do it properly):

1. Make adjustment that you think is appropriate.
2. Go to s stretch of straight gravel road.
3. Engage your CDL or low (the goal is to deactivate your ABS).
4. Drive in a straight line at a decent, but safe speed <20MPH.
5. Lock up the brakes.
6. The other person observes the brakes on lock up.
7. Do the front and rear lock at the same time? Do the rears lock at all? Do the rears lock and not the fronts?
8. Make any further adjustments that are necessary until tests result in front and rear locking up at the same time, or front slightly quicker (that's how I like mine).
9. Following adjustments repeat steps 2-8 as necessary.

Good luck!

 

[AKcruiserfreak]

Great post! Thanks for the help.

TK

latinoguy,
IMHO the best actual test is as follows (and requires two people to do it properly):

1. Make adjustment that you think is appropriate.
2. Go to s stretch of straight gravel road.
3. Engage your CDL or low (the goal is to deactivate your ABS).
4. Drive in a straight line at a decent, but safe speed <20MPH.
5. Lock up the brakes.
6. The other person observes the brakes on lock up.
7. Do the front and rear lock at the same time? Do the rears lock at all? Do the rears lock and not the fronts?
8. Make any further adjustments that are necessary until tests result in front and rear locking up at the same time, or front slightly quicker (that's how I like mine).
9. Following adjustments repeat steps 2-8 as necessary.

Good luck!

 

[Tapage]

[*]Make any further adjustments that are necessary until tests result in front and rear locking up at the same time, or front slightly quicker (that's how I like mine).

Interesting .. I like mines lock the rears before fronts .. ( still have steering ) just a matter of taste.

 

[Atticus]

Interesting .. I like mines lock the rears before fronts .. ( still have steering ) just a matter of taste.

If your rears lock before the fronts on pavement, you could spin out of control. If you have ABS, then it shouldn't matter, but if you're driving without ABS, you definitely don't want the rears locking first.

 

[Atoyot1031]

Interesting .. I like mines lock the rears before fronts .. ( still have steering ) just a matter of taste.

I know you don't have snow & ice.

If you did, you woulda totaled yer 80 many moons ago with yer brakes setup that way.

Here is the first hit I found when I googled the topic (emphasis is mine):

Drive the truck on a dirt or gravel road with no other traffic at about 20 mph and lock up the brakes with someone standing a safe distance away watching your tires. At this point the fronts should lock up and skid while the rear wheels should keep turning.

If this is the case turn the P-valve in half way and try again, if your rear wheels still keep turning when the fronts lock up increase the pressure to the rear brakes 3 turns at a time until the rear wheels start to lock up at the same time as the fronts. If the rears lock up before the fronts after the half way adjustment then turn the valve CCW to decrease pressure to the rear 3 turns at a time until they lock at the same time. At this point you should turn the valve in the decrease direction (CCW) one or two turns.

The idea is to keep your rear tires from locking up and skidding on slippery surfaces under panic stop conditions. If there is too much pressure going to the rear brakes the truck will tend to "fishtail" causing loss of control. Once you determine the proper setting for your particular truck when it is empty mark the number of turns it takes to get to that position from full decrease position and write that number on the adjustment knob with a felt tip pen. Now when you have a load in the back of your truck and need additional stopping power you can screw the valve in a few turns to send more pressure to the rear brakes since you have several hundred pounds more weight holding the rear tires on the road and increasing their traction. Just remember to return it to the same setting as before when you have unloaded the truck.

 

[80t0ylc]

.....Once you determine the proper setting for your particular truck when it is empty mark the number of turns it takes to get to that position from full decrease position and write that number on the adjustment knob with a felt tip pen. Now when you have a load in the back of your truck and need additional stopping power you can screw the valve in a few turns to send more pressure to the rear brakes since you have several hundred pounds more weight holding the rear tires on the road and increasing their traction. Just remember to return it to the same setting as before when you have unloaded the truck.

I believe this part of the procedure refers to a manual valve. Once it is adjusted correctly, ours compensates for load automatically, hence the term: "Load Sensing" Proportional Valve.

 

[Atoyot1031]

You are correct. They are refering to a manual proportioning valve.

However, the setup should be roughly the same (minus the directions on how to turn the knob). See my step by step above for more directly pertinent directions.

However, the end result is the same. Braking should be either 50-50 or (as I prefer) slightly biased to the front. I posted the quote to back up what Atticus and I said in response to Tapage's post. You do not want the rears locking up before the fronts!

That setup would make dangerous.

 

[Tapage]

If your rears lock before the fronts on pavement, you could spin out of control. If you have ABS, then it shouldn't matter, but if you're driving without ABS, you definitely don't want the rears locking first.

I know you don't have snow & ice.

actually we have rain and plenty of it .. but I feel much more comfy if I lock the rears little before fronts .. and when I said little are just a seg ..

And no .. I haven't ABS ..

 

[latinoguy]

latinoguy,
IMHO the best actual test is as follows (and requires two people to do it properly):

1. Make adjustment that you think is appropriate.
2. Go to s stretch of straight gravel road.
3. Engage your CDL or low (the goal is to deactivate your ABS).
4. Drive in a straight line at a decent, but safe speed <20MPH.
5. Lock up the brakes.
6. The other person observes the brakes on lock up.
7. Do the front and rear lock at the same time? Do the rears lock at all? Do the rears lock and not the fronts?
8. Make any further adjustments that are necessary until tests result in front and rear locking up at the same time, or front slightly quicker (that's how I like mine).
9. Following adjustments repeat steps 2-8 as necessary.

Good luck!

thanks everyone who gave advice, This makes sense. I will try to tinker with it this weekend.