still on lspv (1 Viewer)

[PHIL O]

hi all. a brief background. i bled my brakes and it was doing fine for 2 months now. then lately i went on a long trip and maybe was braking aggressively. when i got home my brakes felt spongy. checked around and couldnt find any visual leaks. so i tried adjusting lspv height and checked its boot since thats the last thing i havent checked. and i found out that my lspv is frozen but without any viible leaks. there is no play on the lspv. (see pictures). now i have searched and searched but cant find any thread on anyone fixing their frozen lspv. from what i read around our forums, i thought it was disposable. but as i opened the lspv boot, i see a retaining clip similar to that of an MC. i was thinking of opening it. but i want to be sure if i could get parts for this. what's inside an lspv? does it have rubber cups or orings? i checked with toyodiy.com and the lspv is shown as a whole. no repair kits whatsoever. any ideas and tips you could share? could you share pictures if you have some. thanks. our brakes are really puzzling me

 

[PHIL O]

Mystery no more

Mudders, i didnt see any replies to this post so i thought this was either new to us or just the most neglected brake part we have on our rigs. Anyway, before dissecting the LSPV, i searched the net and asked local suppliers if they had repair kits available for this, but it seems that this unit is diposable once it is shot.
So i planned and executed the project carefully by these steps:
1. Disconnect the LSPV to axle rod by removing bolts and nuts on the axle end and removing bolt, nut and rubber boot (fastened by a clip) on the LSPV end.
2. Remove the three hard brake lines from the LSPV. Catch brake fluid on a container and be carefull not to get brake fluid on yourself. I got some in my eyes and it gave me some burning sensation, washed it off with water. I recommend wearing eye protection too.
3. Remove the LSPV unit. I tried removing the two nuts on the LSPV unit to get it free but it was rusted in and frozen, so i had to remove the LSPV together with its mounting bracket. Remove the four bolts that hold the bracket into place and pull the assembly off.

First picture is the LSPV, the mounting bracket and the mounting bolts (which came off after some pounding).
Second picture is the LSPV to axle rod in its many pieces which i wire brushed with water then air dried.

 

[PHIL O]

4. Dissect the LSPV by removing the retaining clip (A) and pulling off the plastic guide (B) which the LSPV to axle rod slips into. There is also a rubber grommet (C) under the plastic guide. Remove the big bronze nut (D) and tap the LSPV unit on a piece of wood to free the pushrod-piston (E). Separate the bronze nut from a gold cylinder (F).
5. Carefully remove the two o-rings and two rubber cups. Then nylon-brush (I used an old toothbrush) each and every LSPV component with non-detergent soap and rinse with water. Dry with compressed air.
6. The only parts I noticed that needed extra attention was the bronze nut and pushrod-piston that had a rust-like buildup which I filed off and sanded smooth. I also sanded, with a very fine 1000 grit sand paper, the interior of the LSPV.
7. Put everything back in the reverse order.
8. After the assembly, I dabbed some grease on the external moving parts especially where I noticed the rust-like build up on the bronze nut and pushrod-piston. I also coated the mounting bolts with grease before mounting LSPV on bracket
9. Install on rig, connect hard brake lines, mount the LSPV to axle rod, and secure rubber boot with clip.
10. Bleed entire brake system and then adjust LSPV according to FSM.

 

[Ebag333]

Excellent posts. Have you noticed a different after all your work?

 

[PHIL O]

yup Ebag333, it definitely made a significant difference. Actually i adjusted the axle end of the LSPV rod higher by a quarter of an inch before doing the LSPV maintenance. I was impressed by how firm brakes felt afterwards. Though the rig is at stock height, i think adjustment becomes a little slack over time. With that, i thought of giving our LSPV some justice. so i opened it up and gave it the same care the rest of the brake system deserves.
So before we dismiss our spongy feeling brakes to faulty brake masters cylinders (despite extensive bleeding), i would recommend checking the LSPV too.

 

[Aussie cruiser]

Did you replace any of the internal parts such as orings or seals or was it just a clean up job??

 

[PHIL O]

Aussie cruiser, the internal parts showed no visible signs of wear. so i just cleaned them up because crud was building up. just like a master cylinder which wasn't serviced for quite some time. i also sanded off the rust-like build ups. the o-rings look common. one rubber cup also looks like it could just be bought from the auto supply. but the other rubber cup has special castle like grooves on top. maybe to prevent it from sticking or what. am wondering why toyota doesnt sell kits for these

 

[Dutchie]

They actually sell kits... part no. 04477-60010

I replaced my lsvp as it was leaking. While checking the new one I noticed that the little pin sticking out and that touches the rod going the the axle, can be pulled outward if you try a little. Am I correct that this happens under brake pressure and 'how far' it travels before it hits the rod determines the pressure to the rear ?? I think it does but if anyone has any other thoughtd on this ..

 

[jlbuk]

PhilO, how have you verified that it's frozen ?
On mine, the nipple in the centre only pushes itself outwards, when someone else (unless you have 10 foot long limbs) is standing on the brakes with the engine running. The nipple then retracts itself when your assistant gets off the brake. From the retracted position, it won't move any further in.

 

[Cattledog]

They actually sell kits... part no. 04477-60010

I replaced my lsvp as it was leaking. While checking the new one I noticed that the little pin sticking out and that touches the rod going the the axle, can be pulled outward if you try a little. Am I correct that this happens under brake pressure and 'how far' it travels before it hits the rod determines the pressure to the rear ?? I think it does but if anyone has any other thoughtd on this ..

Thank you!

I asked Cdan about a rebuild kit and was told there was no rebuild kit. The new valve was expensive. Maybe Cdan could add this part number to the us parts database.

 

[96r50]

Actually, that kit doesn't have any of the internal parts for the LSP&BV, just the bushings/boots for the arm.

 

[Dutchie]

Actually, that kit doesn't have any of the internal parts for the LSP&BV, just the bushings/boots for the arm.

OK, I did not know, thought it had the internals too....

 

[PHIL O]

PhilO, how have you verified that it's frozen ?
On mine, the nipple in the centre only pushes itself outwards, when someone else (unless you have 10 foot long limbs) is standing on the brakes with the engine running. The nipple then retracts itself when your assistant gets off the brake. From the retracted position, it won't move any further in.

jlbuk, the first time i posted this, i knew little about how an LSPV operates. so i thought the piston was stuck simply by looking at it because there was corrosion at the outer part. At first i thought it was supposed to rest on the LSPV to axle rod and move in and out as weight varies. !!! But when i opened the LSPV, i realized, as you have said that the piston should push itself outwards as brake padal is pushed. So the only thing actually frozen here was the mounting bolts that hold the LSPV on to the mounting bracket making it impossible to adjust the height.

 

[PHIL O]

you're right guys, no rebuild kits for the LSPV. Toyota designed this to last forever. though i hope someone thinks of making a repair kit for this since it isnt that complicated. A new LSPV unit is expensive considering its size and function