Author Topic: quick rear drum brake question (Read 13013 times)

SQUIRREL MONSTER · « **on:** Jan 19, 2006, 10:30:06 PM »

hey guys. im in the middle of installing the new (to me) 87 rear end onto my 84 x-cab. situation is, im getting low pedal when hitting the brakes, in fact they reach the floor. question is, with the new 87 rear end will i need to upgrade my brakes master to the 87 as well? or could this be a result of just air in the line along with misadjusted brakes??

sorry if its a constantly asked question but i didnt find the exact answer when i searched for it...

thanks.

MiniSimp · « **Reply #1 on:** Jan 19, 2006, 10:32:43 PM »

Sounds like air in the lines.

Bleed in this order:
Left rear
Right Rear
LSPV (Load Sensing Proportioning Valve)
Right Front
Left Front

It might take 3 cycles to get all the air out, keep an eye on your fluid level when you bleed also.

SQUIRREL MONSTER · « **Reply #2 on:** Jan 19, 2006, 10:38:52 PM »

ah, ok so the fronts will need it as well??? thanks. i will try that tomorrow and see what happens and report back. thanks!

i wasnt sure if i needed to change the master cylinder to a bigger one with the ifs rear drums eventho i still have the 84 master? i know the brakes are diffrent sizes but i didnt think that should matter

MiniSimp · « **Reply #3 on:** Jan 19, 2006, 10:40:32 PM »

That would not affect the pedal going to the floor.
That's just air in the lines.

eightyfive · « **Reply #4 on:** Jan 20, 2006, 02:29:51 AM »

only when you go v6 caliper in front or disc in back is when you have to change master..and booster if you want easier braking power.....drums, ti dont think will even result in noticable braking power....

bruiz05 · « **Reply #5 on:** Jan 20, 2006, 03:16:14 AM »

Ok this is something that alot of people are misslead by. when you change over to a 86 or newer rear axle your rear wheel cylinders are larger than the ones that came factory with yours, the drums are larger so they had to make the wheel cylinder larger to get more volume (not pressure) to the wheel cylinders. so what you need to do is scrap your master and get the FJ80 non abs master cylinder. This master is a one inch bore vs your 15/16. this will get your brakes the volume it needs and back the way they used to be and if you ever change over to vented front rotors or rear disc you will not have to change anything. Make sure when you install the new master you need to bench bleed it prior to installing and then bleed it on the vehical at the lines and then bleed each of your brakes starting at the RR, LR, RF, LF. I also suggest getting rid of the paporioning valve at the rear and using an adjustable one, factorty ones like to get internal leaks that suck air but dont leak fluid.

Good luck

SQUIRREL MONSTER · « **Reply #6 on:** Jan 20, 2006, 09:51:38 AM »

thanks for all the help guys! i will try to re bleed the system as instructed prior. if i do not like how it turns out, i will head down to my local salvage yard and pick up the FJ master.

fourwd1 · « **Reply #7 on:** Jan 20, 2006, 09:56:42 AM »

The actual correct bleeding order is -
RR
LR
RF
LF
LSPV

You don't have to upgrade the MC on your 84 for either the IFS rear w/larger brakes or adding V6 IFS calipers up front.

I have both on my 84 Runner and it stops my 36" TSLs just fine.

Just adjust the rear shoes properly and bleed correctly.

SQUIRREL MONSTER · « **Reply #8 on:** Jan 20, 2006, 10:01:53 AM »

ah ok, i whent off of memory when i listed the last post wich didnt help

haha. ill try it soon as i find a dummy to push the pedal to bleed the brakes

kneedownnate · « **Reply #9 on:** Jan 20, 2006, 08:06:15 PM »

Quote from: bruiz05 on Jan 20, 2006, 03:16:14 AM

I also suggest getting rid of the paporioning valve at the rear and using an adjustable one, factorty ones like to get internal leaks that suck air but dont leak fluid.

Mine has surpassed this and now marks it's spot! On my 80 I needed a new mc, had an 86 I was parting out with a 13/16 mc so I put it on, and just the other day I finally switched it out with a 1" from a supra. I still need to bleed it more to see if it made a difference, but right now it's pretty much the same.

79coyotefrg · « **Reply #10 on:** Jan 21, 2006, 08:23:06 AM »

when i changed mine to a celica master with 1 inch bore my stopping distance was cut in half, i can lock up all 4 if i want and cand stop quikly going backwards

it came from a 80 celica,

SQUIRREL MONSTER · « **Reply #11 on:** Jan 21, 2006, 01:37:18 PM »

Quote from: fourwd1 on Jan 20, 2006, 09:56:42 AM

The actual correct bleeding order is -
RR
LR
RF
LF
LSPV

Quote

Sounds like air in the lines.

Bleed in this order:
Left rear
Right Rear
LSPV (Load Sensing Proportioning Valve)
Right Front
Left Front

It might take 3 cycles to get all the air out, keep an eye on your fluid level when you bleed also.

soooo........ wich way is it?? i just need to reattach the front lines to be done and need to bleed em' so wich way is the correct way to do em? or are either way fine?

bruiz05 · « **Reply #12 on:** Jan 21, 2006, 02:03:13 PM »

the easyest was to remember how to do it is the farthest one from the master so that would be:
RR
LR
RF
LF
this is the only way to do it right!

SQUIRREL MONSTER · « **Reply #13 on:** Jan 21, 2006, 05:01:31 PM »

ah cool! so where does the BPV fall into this order? shouldnt it be bled through the process of bleeding the rear?

jimbo74 · « **Reply #14 on:** Jan 21, 2006, 05:15:43 PM »

Quote from: SQUIRREL MONSTER on Jan 21, 2006, 05:01:31 PM

ah cool! so where does the BPV fall into this order? shouldnt it be bled through the process of bleeding the rear?

BPV? are you talking about the LPSV? Load Proportioning Sensing Valve

Quote from: fourwd1 on Jan 20, 2006, 09:56:42 AM

The actual correct bleeding order is -
RR
LR
RF
LF
LSPV

DTB · « **Reply #15 on:** Jan 21, 2006, 05:20:47 PM »

Quote from: jimbo74 on Jan 21, 2006, 05:15:43 PM

BPV? are you talking about the LPSV? Load Proportioning Sensing Valve

BPV=brake proportioning valve

bruiz05 · « **Reply #16 on:** Jan 21, 2006, 06:30:12 PM »

bleed the system first and check your pedal and if its still a little soft then you can crack the lines and bleed it but most of the time you dont need too.

SQUIRREL MONSTER · « **Reply #17 on:** Jan 21, 2006, 09:41:13 PM »

Quote from: DirToyBoy on Jan 21, 2006, 05:20:47 PM

BPV=brake proportioning valve

lol yea, thats what i meant by it but really meant to say the LPSV (Load Proportioning Sensing Valve) ....... or whatever the heck its called

anyhow, i think i bled all the air out of the system but like a true knuckle head i forgot to adjust the rear drums before bleeding the whole system.

but, i guess ill just readjust the drums and see if it needs anymore bleeding of the system.

also.... this is just a hunch but with the diffrent front end i just swaped in, im gonna need to realighn it arent i? heres where i figured i did. the front is on a mega oversteer position on top of the tires chirping down the road. took a measurment from the front tires on the front face and got 51" inches. then took a measurment from the back face of the tires and got 49....... plus my front end looks like this below.... you can tell the toe is way out on it. ill need to make a quick adjustment before i even take it to the shop its that bad

79coyotefrg · « **Reply #18 on:** Jan 22, 2006, 07:29:56 AM »

just rotate your tierod so it sucks the front in when you get 50 inches front and rear your golden

oh yea and its called a LSPV Load sensing propotioning valve

79coyotefrg · « **Reply #19 on:** Jan 22, 2006, 07:30:22 AM »

and mine was bypassed years ago

SQUIRREL MONSTER · « **Reply #20 on:** Jan 22, 2006, 12:02:11 PM »

haha, sweet! will do!

also guys; to adjust the rear drums...... i belive yer supposed to lift the rear (keeping in mind my rear is locked at all times) spin the tires and adjust the star gear till it "locks up" the tire correct? then back it off about 5-8 clicks? am i correct or

79coyotefrg · « **Reply #21 on:** Jan 22, 2006, 02:09:25 PM »

its not easy to back them off but that would do, i always jack it up and at the first hint of drag i stop and back it off about half a turn

SQUIRREL MONSTER · « **Reply #22 on:** Jan 22, 2006, 03:56:47 PM »

well, got em adjusted to where they just drag a bit. but im still gettin low peddal at first pump. i think there still may be air in the system..... imma try and re bleed right now, see what it does.

79coyotefrg · « **Reply #23 on:** Jan 22, 2006, 05:03:58 PM »

is your master cylinder new ?? if not go to a salvage yard and get one from a celica, they are cheap and have a 1 inch bore, but yea you probably still have some air in your lines, or your front pads are wore, you didnt have your rotors turned did you ??

SQUIRREL MONSTER · « **Reply #24 on:** Jan 22, 2006, 05:42:30 PM »

rotors are new, so are the pads. it got dark before i got a chance to bleed em but my buddy said he'd get me a pressure bleeder tomorra to do em.

i think i may have tracked some crud through the disks to so ill try and run some cleaner over them and scuff em up with a pad tomorra.

79coyotefrg · « **Reply #25 on:** Jan 22, 2006, 05:45:26 PM »

tell me how you are bleeding them

SQUIRREL MONSTER · « **Reply #26 on:** Jan 22, 2006, 06:07:42 PM »

well, last night, i think i may have screwed up and done em LR, RR, RF, LF.

i think the front should have done in opposite order but i was goin in the order from farthest from the master to the closest. what would you suggest? will using a pressure bleeder be better? or should i rebleed them via gravity in LR, RR, LF, RF order?

i could go out and do em right now..... tho someone musta ordered the damn snow cus its cold as well anyhow. if i can do a quick gravity bleed ill go bust the lines right now.

79coyotefrg · « **Reply #27 on:** Jan 22, 2006, 06:13:01 PM »

ok get somebody to help you, i have never followed a specific order but

have them pump the brakes 2 or 3 times then hold them down hard ,you will be under there ready to bleed, when they mash it the last time and hold it, you break open the bleeder, then tell them ok, and they can pump again i do this on each wheel till i get no more air, but keep a check after 5 or 6 times that your fluid doesnt run dry or you'll have to start over,

i have never believed in pressure bleeders or gravity,always use the buddy system

79coyotefrg · « **Reply #28 on:** Jan 22, 2006, 06:14:53 PM »

all bleeders should be tight befor you start this type of bleeding, but it will get all the air out

SQUIRREL MONSTER · « **Reply #29 on:** Jan 22, 2006, 06:48:10 PM »

yea, i didnt have no body to help me out yesterday and needed to get it done so i gravity bled them. ill have someone help me out tomorrow instead and do it.

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