Yet another LSPV/ABS delete how to... (2 Viewers)

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A few years ago, I removed my LSPV, installed a union, and removed the sense line. Instant braking improvement.

A little more than a year ago (or two) I had to replace my front calipers and got some air in my ABS pump. I bled the unit as good as I could but the pedal was soft and the brakes pulled to the left.

In Nov, I committed to removing the ABS pump completely and installing a manual proportioning valve. The valve was $40 and the brake line straightener was $40. Factory lines were reused to connect the proportioning valve. Afterwards, braking is consistent and strong. However before I adjusted the proportioning valve, the rear would lock up first and the truck would start rotating. I marked the top of the proportioning valve with paint and rotated the dial two full turns for less rear brake. Braking is better but I haven't had a chance to test emergency stopping again.

I really love the simplified system. Disabling the ABS light is the final step.
I took the bulb out and put it in my shift indicator so the green D would light up on the cluster when it was in drive. Mine had burned out some years prior
 
I took the bulb out and put it in my shift indicator so the green D would light up on the cluster when it was in drive. Mine had burned out some years prior
Like many, I haven't had a D light since owning the truck. It might freak me out seeing one.
 
I'll be doing more work today on my brakes. A bit of history. I originally just removed the ABS module and put a T in and brakes were still okay with the ABS MC. Much later I replaced booster and installed proper 80 series MC for non ABS w/ disc brakes. Pedal felt awful after a solid bleed. Today I will be deleting the LSPV and installing proportioning valve. I got the Allstar 48025 manual valve that comes with 1/8 NPT fittings. I found some 1/8 NPT/10mm inverted flare adapters (EAR-02102ERL) from Summit so I wouldn't need to have mismatched lines. Also trying out a T100 non ABS MC.
Let you know how it goes when I get it sorted later today, hopefully.
 
I'll be doing more work today on my brakes. A bit of history. I originally just removed the ABS module and put a T in and brakes were still okay with the ABS MC. Much later I replaced booster and installed proper 80 series MC for non ABS w/ disc brakes. Pedal felt awful after a solid bleed. Today I will be deleting the LSPV and installing proportioning valve. I got the Allstar 48025 manual valve that comes with 1/8 NPT fittings. I found some 1/8 NPT/10mm inverted flare adapters (EAR-02102ERL) from Summit so I wouldn't need to have mismatched lines. Also trying out a T100 non ABS MC.
Let you know how it goes when I get it sorted later today, hopefully.
I am using a T100 non ABS master in my LX, but I am running 5th gen 4Runner calipers thst have a larger bore than the 80 series calipers. So far so good.
 
I'll be doing more work today on my brakes. A bit of history. I originally just removed the ABS module and put a T in and brakes were still okay with the ABS MC. Much later I replaced booster and installed proper 80 series MC for non ABS w/ disc brakes. Pedal felt awful after a solid bleed. Today I will be deleting the LSPV and installing proportioning valve. I got the Allstar 48025 manual valve that comes with 1/8 NPT fittings. I found some 1/8 NPT/10mm inverted flare adapters (EAR-02102ERL) from Summit so I wouldn't need to have mismatched lines. Also trying out a T100 non ABS MC.
Let you know how it goes when I get it sorted later today, hopefully.

Just out of curiosity, could you remove the LSPV and NOT install a proportioning valve to see if you really need it? Given our phat pigs, I'd think that locking up the rears before the front would take a lot of effort, no?
 
Just out of curiosity, could you remove the LSPV and NOT install a proportioning valve to see if you really need it? Given our phat pigs, I'd think that locking up the rears before the front would take a lot of effort, no?
Couldn’t say as I seem to be testing out every method as I go through this.
Having said that when I got everything back together just now I left the valve set all the way to “less brake” and went for a drive around the hood. It felt awful and I adjusted it a few time on my way back home. I have it probably half way clockwise “more brake” now and it feels good. Still need to find some dirt as my gravel driveway is not long enough get up to speed. My neighbor was looking at me funny as I was attempting it. Damn dump truck tranny!

Valve and 10mm inverted flare adapters.
FEF0B85B-C983-42ED-A42A-5900EE1302BD.jpeg

still need to make a bracket for valve.
9681091D-EEED-4A26-96FB-3B855FFF7D2A.jpeg


Simple union to bypass LSPV
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Pulled sense line and few other lines to get rid of the T I was using after deleting ABS
695FC980-F0EF-49CB-82B9-9F1E6DF64C72.jpeg
 
Just out of curiosity, could you remove the LSPV and NOT install a proportioning valve to see if you really need it? Given our phat pigs, I'd think that locking up the rears before the front would take a lot of effort, no?
But if you already have the system open why not add it now, instead of later requiring you to bleed the system again?
 
I deleted my LSPV and had fantastic consistent braking. I didn't need a proportioning valve and emergency braking behaved exactly as expected.

I definitely needed a proportioning valve after I deleted my ABS pump last November. Emergency braking with full power to the rear cause the rear brakes to lock and the truck to rotate.
 
I deleted my LSPV and had fantastic consistent braking. I didn't need a proportioning valve and emergency braking behaved exactly as expected.

I definitely needed a proportioning valve after I deleted my ABS pump last November. Emergency braking with full power to the rear cause the rear brakes to lock and the truck to rotate.
How much valve adjustment did you have to do to get it dialed in?
 
How much valve adjustment did you have to do to get it dialed in?
There is a lot of adjustment in the proportioning valve. I painted the wilwood "w" with finger nail polish and as indicator and rotated the knob to full open. This was not good. I've turned it two rotations from full to decrease braking to the rear but haven't been able to test it again.

If the rear locks before the front, I will turn it two more times and continue this until I get the front to break lose first.
 
Just out of curiosity, could you remove the LSPV and NOT install a proportioning valve to see if you really need it? Given our phat pigs, I'd think that locking up the rears before the front would take a lot of effort, no?
I went this route. I still have the ABS so no issues with rears locking up. I am pretty happy with my set up.
 
I went this route. I still have the ABS so no issues with rears locking up. I am pretty happy with my set up.
Immediately after deleting my LSPV and before I got air in my ABS pump, I was amazed at the power of the brakes and how quickly the truck would come to a stop. ABS didn't even activate but I did several 50 to 0 stops that had me gripping the steering wheel and had stuff flying around in the truck.
 
Just out of curiosity, could you remove the LSPV and NOT install a proportioning valve to see if you really need it? Given our phat pigs, I'd think that locking up the rears before the front would take a lot of effort, no?
First understand I am not an advocate of altering the ABS/LSPV system on the 80, in good shape it works perfect, but let's not get into that, anything worth (and not worth) saying has already been said.

It is not about locking the rears before the front, all things being equal the rear will always lock before the front. Fitting a manual proportioning valve is at best a get around and is completely pointless. Once the 'testing' (that alone is a whole new subject) is carried out and the valve is set, the moment you add weight for example four passengers the pressure to the rear brakes will be maintained to assist the front brakes, less weight and the rear rises taking weight off of the rear wheels triggering the lock up unless the LSPV reduces this pressure.

So, where do you set the manual valve, minimal pressure to the rear brakes preventing lockup up at anytime but shifting the braking effort to the front brakes, or full pressure and hope you are fully loaded at all times, particularly during an emergency stop, or somewhere in between, i.e a guess?

Regards

Dave
 
First understand I am not an advocate of altering the ABS/LSPV system on the 80, in good shape it works perfect, but let's not get into that, anything worth (and not worth) saying has already been said.

It is not about locking the rears before the front, all things being equal the rear will always lock before the front. Fitting a manual proportioning valve is at best a get around and is completely pointless. Once the 'testing' (that alone is a whole new subject) is carried out and the valve is set, the moment you add weight for example four passengers the pressure to the rear brakes will be maintained to assist the front brakes, less weight and the rear rises taking weight off of the rear wheels triggering the lock up unless the LSPV reduces this pressure.

So, where do you set the manual valve, minimal pressure to the rear brakes preventing lockup up at anytime but shifting the braking effort to the front brakes, or full pressure and hope you are fully loaded at all times, particularly during an emergency stop, or somewhere in between, i.e a guess?

Regards

Dave

Excellent points Dave, well stated. But do keep in mind that some of us have dedicated wheeling rigs and are always in the rear "heavy" mode. So, for someone like me, LSPV concept can be tossed out the window in favor of better and more predictable braking.

I'm rather surprised at how effective the braking has become for some of the 80s on this post right after removing the LSPV. If we crank the load sensing lever fully to one position (heavy cargo perhaps?), does that mean the valve is in the correct operating position for max braking in the rear? I don't recall which position my lever is at currently, probably all the way up?
 
I had the LSPV arm bolted in the up position for ages before I removed the unit. Like @alia176 mentioned my rig is lifted and always on the heavy side. Fairly noticeable difference after the removal. Not sure if my valve was not performing as designed or if removing it just improved the over all brake performance. Either way i am very happy with my system.
 
@alia176 I hear you about permanently heavy vehicles and yes if your valve is fully open then maximum braking effort is being applied to the rear brakes.

The first problem I see is about balance, it is a fact that the front will dip during heavy braking and the rear lift, but it is about the amount of dip/lift dictated by not only the braking effort but also the surface you are braking on. A fixed valve cannot cope with the variables involved for example a wet surface, you brake hard to prevent an accident on the motorway, there may not be enough traction to change the vehicles body/axle position,, the LSPV keeps pressure reduced to the rear brakes, but in a fixed valve set at fully open you still have full braking effort to the rear wheels regardless of whether loaded or not, the result is the rears may lock spinning the vehicle.

Another point is that modern vehicle brakes tend to be excellent and so it is natural to get out of a compact with great brakes and get in an 80 with a braking system that was designed over 30 years ago, add in you are also stopping a vehicle that weighs a lot more than the compact you just got out of, so comparisons are unavoidable. Being a mechanic I might drive a dozen different vehicles every week, and there seems to be very little difference in the braking characteristics between them and this is not a coincidence, you may find the exact braking system brand on a range of different marques.

In my opinion if the 80 brakes have a flaw it is in heat dissipation, I can drive my diesel 80 quick enough around the local area with no passengers and still get brake fade, all four brakes hot and smelling. I fitted dimpled and grooved discs, all new calipers and pipework, did it help? If I am brutally truthful I spent over 2000 GBP and reckon I gained a small improvement, all I really got out of it was peace of mind that the whole system was in good shape. If 'spirited' driving is in your nature then in my opinion is physically bigger brakes to help with the heat are needed and not removing components that have been tried and trusted over many years.

A final note, fitting bigger wheels and tyres to an 80 seems to be a 'right of passage', and is clearly the norm for many if not most of the forum members, but this simple bolt on change will increase the braking distance for a given pedal pressure, then along come the complaints that the brakes are no good.

Regards

Dave
 
Has anyone deleted the ABS but left the LSPV in place? Mine seems in decent shape, truck only has 90K on it (though I admit miles might not be the issue), not leaks, etc.
 

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