Author Topic: Stop!!!! No rear brakes! (Read 5414 times)

dentmagnet · « **on:** Jan 04, 2011, 12:06:12 PM »

OK, here's the story. Changed the rear axle to one with bigger drum brakes. Found a 1" bore master cylinder here locally from an FJ80. Don't see any residual valves on it for the rear drum brakes. Do I even need one? Lol, apparently it needs something since the rear brakes don't work at all. Is there a residual valve that can be added to the master cylinder? The master cylinder is just tapped for the brake line size so I don't see any way to add a residual valve to it. I still have the lsv in the rear with the arm tied in the up position. Anyone had similiar problems? This is on an '81 Trekker with 35" tires. I hope someone can point me in the right direction. This is my first Toyota. Stuff is a little different on this thing!

Dirt Mover · « **Reply #1 on:** Jan 04, 2011, 12:45:07 PM »

Pull the emergency brake and see if they work mechanically, if so check out the FAQ on brake bleeding. if they still don't work after that I would look at the lsv.
The only other problem I've had is when I lost the lining on one side with a welded rear end the brakes would work at first, then go to the floor.

Slolyfe · « **Reply #2 on:** Jan 04, 2011, 01:00:06 PM »

If you take the drum off, there is a star type of ratcheting thingy which adjusts the pads out as they wear down. This can also be accessed through an oval shaped inspection port on the back side of the dust cover, after you remove the little rubber plug.

Jack your rear end up and spin your tire. Keep adjusting this ratcheting thing with a screw driver (flathead) untill you can hear the brakes slightly hitting the drum. Do this to both sides. Should get you pretty close or at least you can rule that out.

Pictures to come.

OOPS · « **Reply #3 on:** Jan 04, 2011, 01:03:17 PM »

Did you bleed the LSPV?

"...This is from the FSM and it works great..."
1. Drivers side rear
2. Passenger side rear
3. Passenger side front
4. Drivers side front
5. LSPV (Load sensing proportioning valve)

Drum brakes do not require a residual valve, rear discs may.

OOPS · « **Reply #4 on:** Jan 04, 2011, 01:06:21 PM »

Quote from: Slolyfe on Jan 04, 2011, 01:00:06 PM

Keep adjusting this ratcheting thing with a screw driver (flathead) untill you can hear the brakes slightly hitting the drum. Do this to both sides.

The correct way is to adjust them up until they are tight, then back them off to slight drag. That centers the shoes in the drum giving you max contact.

Slolyfe · « **Reply #5 on:** Jan 04, 2011, 01:10:11 PM »

The adjusting port.

The screwdriver is pointing to the ratcheting thing I mentioned earlier.

Hope this helps if not you now have 6 mins of my life.

Slolyfe · « **Reply #6 on:** Jan 04, 2011, 01:11:20 PM »

Quote from: OOPS on Jan 04, 2011, 01:06:21 PM

The correct way is to adjust them up until they are tight, then back them off to slight drag. That centers the shoes in the drum giving you max contact.

True but I hate backing that thing off. Hahahah

junya92toy · « **Reply #7 on:** Jan 04, 2011, 01:32:17 PM »

I usually adjust the rear breaks when its all apart, just turn the adjuster until you can barely get the drum on.

dentmagnet · « **Reply #8 on:** Jan 05, 2011, 07:31:08 AM »

Thanks for all the replies! I put new shoes on it and wheel bearings before I put the axle in. I set the shoes so I could just barely get the drum on and bled all the brakes 4 times. The emergency brake still doesn't work either, of course, I had to jury rig a longer bracket on the wheel since the axle I installed is 3" longer than the old one was. Only thing I didn't do was bleed the lsv. Not being a Toyota expert, I had never run across an lsv before. I figured it had to be some kind of proportioning valve. I'll try bleeding that and set the shoes up again. Thanks! I'll let u know what worked. The e-brake isn't too big of a deal though, as I also have a line lock I'll be installing, IF I ever find fittings to get me to 1/8" pipe threads, lol.

yotaneck13 · « **Reply #9 on:** Jan 05, 2011, 11:47:59 AM »

try letting your lsv down to where it would be if it was connected to your axel or you can just completly do away with it all together and get a aftermarket one with the screw type adjustment i dont even run the lsv at all and im runnin 33's they just lock up a lil faster on wet pavement

OOPS · « **Reply #10 on:** Jan 05, 2011, 11:52:08 AM »

I had to jury rig a longer bracket on the wheel since the axle I installed is 3" longer than the old one was.

Most of us have done that.

Only thing I didn't do was bleed the lsv.

The LSPV is the seconded highest componet in the system. That is why you bleed it last, Air travels up in the system

The e-brake isn't too big of a deal though, as I also have a line lock I'll be installing, IF I ever find fittings to get me to 1/8" pipe threads, lol.

Line locks are not a legal e-brake, but good for short term use. You can also get adapters to take it from metric to SAE. Try adjusting the brake shoes up tighter and adjust the cable on the bell crank for the e-brake. With the extensions on the e-brakes the handle has to pull futher to set the e-brakes.

dentmagnet · « **Reply #11 on:** Jan 05, 2011, 05:24:34 PM »

Re-bled the brakes and set the shoes up tighter. Helped a bunch! Still can't quite lock em up but works wayyy better! What's the best way to bleed the lsvp? Don't really see an easy way to let air out. There's a cap on top, but I didn't mess with that. BTW, put the line lock on the front brakes, mostly for winching but it will hold for short periods. The e-brake works now, mostly. Still a little weak, though and there isn't a lot of adjustment left on it.

OOPS · « **Reply #12 on:** Jan 06, 2011, 08:09:03 AM »

Quote from: dentmagnet on Jan 05, 2011, 05:24:34 PM

Re-bled the brakes and set the shoes up tighter. Helped a bunch! Still can't quite lock em up but works wayyy better! What's the best way to bleed the lsvp? Don't really see an easy way to let air out. There's a cap on top, but I didn't mess with that. BTW, put the line lock on the front brakes, mostly for winching but it will hold for short periods. The e-brake works now, mostly. Still a little weak, though and there isn't a lot of adjustment left on it.

There is a bleeder on it just like the brakes.

Dirt Mover · « **Reply #13 on:** Jan 06, 2011, 08:26:53 AM »

Sounds like bleeding and adjustments are getting you closer to what you need. Once you know that isn't the problem I would look at the other components in the system [lspv, MC, etc.]
This is one of the most common problems so there is plenty of tech and options when the time comes

dentmagnet · « **Reply #14 on:** Jan 06, 2011, 10:40:57 AM »

The brakes worked great before i changed the axle to one with bigger brakes on it. the master cylinder is a new 1" bore for an fj80. same one marlin sells. looks like it's just an issue of air in the lines, or the lspv. I looked for a bleeded on it but haven't found it yet. I'll look some more today and bleed stuff again after I drive it a bit. Stops pretty good right now, just won't quite lock em up on dry pavement. I'll also set the rear shoes up another couple notches. It's getting really close to good now.

dentmagnet · « **Reply #15 on:** Jan 06, 2011, 10:50:00 AM »

btw, just where does the arm on the lsv normally sit on a stock truck? I have it all the way up right now. having never had a toyota, the lsv is a learning experience for me. i guess if it gives me much grief, i'll pull it off and go with an adjustable proportioning valve, at least I know about those, but no sense spending more money on that if i can make the lsv work.

Slolyfe · « **Reply #16 on:** Jan 06, 2011, 01:10:50 PM »

If its all the way up, your rear end is getting full braking.

Rocksurfer · « **Reply #17 on:** Jan 07, 2011, 04:59:42 AM »

With 35's braking will be deminished anyways in the rear, I would bleed the lspv then cut the arm and tie it in the full up position with a tie wrap. That's what I do.

dentmagnet · « **Reply #18 on:** Jan 07, 2011, 07:03:54 AM »

yep. mine is cut off and tied up with steel strap. I just need to find the bleeder on it. Darned thing is pretty rusty and crusty.

Slolyfe · « **Reply #19 on:** Jan 07, 2011, 11:05:28 AM »

Mines on the garage floor, or did it make it to the dumpster at work?

dentmagnet · « **Reply #20 on:** Jan 07, 2011, 01:03:15 PM »

OK, it's official. The lsvp on this 1981 Trekker has NO bleeder on it. All thats there is the lines going in and coming out, 2 mounting bolts, the arm that used to go to the axle , a plug of some sort on the top that looks like it would take about a 1" socket to turn and the rubber boot that covers all the lower operating joints for the arm. That's it, that's all there is. Do i need to remove the plug and add brake fluid? I did a search here for rear brake bleeding, bleeding the lspv, lspv, brakes and so on and so forth. Came up with nothing. I found a picture of one doing a google search but it was a newer one. I saw the bleeder on it, but mine has none. So, how the heck do I bleed this thing? BTW, a search for lspv comes up asking if I meant "lisp"

Mountain Cop · « **Reply #21 on:** Jan 15, 2011, 09:55:28 AM »

You can get a proportioning valve and residual from Davez off road, and just eliminate the LSPV altogether. No valve=no bleeding. I'm running without ANY proportioning valve right now, and it is a bit squirrelly, but manageable.

yotaneck13 · « **Reply #22 on:** Jan 15, 2011, 12:12:13 PM »

crack all your bleeders and pull your master cylinder cap fill it up and leave it sit over night thiss will get all the air out then jus bleed them a few times and it should have breaks if not idk... did you bench bleed your new master before you installed?

dentmagnet · « **Reply #23 on:** Jan 15, 2011, 07:52:36 PM »

Yep. Bench bled rthe master cylinder before I installed it. The brakes are doing somewhat better but there seems to still be a problem. I think that lspv needs to go. I'm sure it has some air in it and there is no way to bleed it. Been driving it around and keep bleeding the brakes in hopes of eliminating more air. It's sitting this weekend, though. I'm working on some rock sliders. Should finish welding those on tomorrow then I'll bleed and see if stuff improves. Been trying to figure out how to post some pics her, but I've been a little busy and haven't had a lot of time. Maybe after I get the sliders on.

Dirt Mover · « **Reply #24 on:** Jan 15, 2011, 08:02:46 PM »

Are you bleeding by yourself with a pump or having someone pump the pedal? I've read that the pumps don't always get all of the air out. I like the pump for flushing the line then getting someone to help cause you get feedback on the feel of the pedal.

dentmagnet · « **Reply #25 on:** Jan 17, 2011, 09:36:49 PM »

I have my girlfriend pumping the brakes. Seems to work better doing it that way, I agree. Never tried the auto bleeders. Seems like a good idea at least until a speck of crud eventually gets in them.

sabatoa1 · « **Reply #26 on:** Apr 11, 2011, 07:25:01 AM »

If I was you I would eliminate the LSPV. I have done it and it is very easy, you just take off LSPV plug the t that runs to it from the front right brake, and use the porportioning valve off first gen toyota. This decreases the amount of brake fluid that is needed to make your brakes function giving you better brakes.

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