LUVTruck.com

not sure what y problem is but i think it is the vacuum brake booster giving out.
recently my brakes started to get a "fade" feeling, where i would push the brake but it would pretty much go to the floor, then when i lifted off and hit the brake again it would grab and lock the tires up. and when sittign at an idle with my foot on the brake it seems to iddle a bit choppy (like a vacuum leak issue). and more recently when i hit the brake it pretty much waits till about an inch from the bottom of the pedal stroke before it finally grabs the brakes, and has been locking the back wheels up...

is it the brake booster? and if so do i need to replace it with a luv booster or will others fit??

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

I had a similar problem. I purchased a replacement at rockauto.com. Works great too. I think it was $80 + $10 core. I wouldnt know if there are any other boosters that will bolt on.

_________________
1980 Luv Mikado 2wd stock
1995 Ford F150 XLT 4X4

If your booster is bad, you should have a high, firm pedal. If the rears are locking up, you may need to rebuild/replace the wheel cylinders and springs. Also the brake hose to the back can get flaky.

Just had a similar problem with my sons '80 Luv....excpept for the locking up the brakes issue. Brakes were fading but could be pumped up. He had a bad master cylinder. Could get a rebuild kit from Napa for $48 or a replacement master cylinder for $45. Guess which way we went. It took about an hour to replace it and then bled the brakes. Fixed the problem.

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

well if they are only 50 or so bucks i will just grab a new booster. the lines were all bled recently. and i checked the brake pads. they are worn but not nearly gone...

and when i said "lock up" the rear end has no weight in it at all... the tires skid most of the time. its liek the brakes dont have a progression in clamping power that stays stable... you can put a set amount of pressure on the pedal and it wont stay the same amount of brake clamping.... you have to get closer and closer to the floor to keep slowing down. which is why i thought brake booster. and sitting at a stop light on any kind of slope is sketchy because unless i have it HELD to the floor it can (but doesnt always) start to roll unless the brake is at the bottom of the stroke

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

That sounds more like a master (or maybe wheel) cylinder gone bad to me.

_________________
OK, I'm over it. Where's the beer?

best way to check? i looked all around and i dont see any leaking fluid from any of the brakes or around the master cylinder.

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

X2
System of a bad master cylinder.

All the booster does is help you push on the master cylinder. If the master cylinder cup goes bad, the fluid just leaks from one side of the piston to the other. None comes out. If you hold steady pressure on the pedal and it keeps going down, without losing fluid, it is the MC.

Brake fade is when you have a solid pedal, but the truck doesn't stop, usually from overheating the lining. I think all your problems sound like bad hydaulics or springs.

Pretty rare for a booster to go bad...(not impossible, they do ocassionally but not often) but I still believe the master cylinder would be my first check. When you remove the master cylinder be careful with the gasket between the master cylinder and booster, I couldn't find a replacement one so luckily the old one was still usable. You could of course make a new one if you have to. Rear wheels locking up, I would remove the rear wheels and make sure there is no leakage from the wheel cylinders or rear axle seals. Do they release when you let off the break pedal or hang up for a while?

_________________
In life there is the "Way things should be" and then "There's the way they are".

2005 Silverado 3/4T Crew Cab
1981 Luv 2WD
1979 Luv 4x4 Currently going through Open Heart and Cosmetic surgery
1995 Roughneck JetBoat
1981 Luv parts trk

thanks guys
that helps a lot. now i just gotta find a new MC

scratch that: rock auto has them for $30-50.. will have one on payday

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

A1 Cardone remaned brake master cylinder
part number : 11-1817

O'Reilly's has it for 33.99 forgot what the core is. like 25 bucks.

library computer won't let me post links...

_________________

To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!

oh well i'll give them my POS for a core XD

oh and i do have that air rail. i dont think the valve on it is any good but the rail is fine.

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

When you change out the master cylinder make sure you check/adjust the length of the rod that comes out of the booster into the back of the MC. It sets to a certain length from the front of the booster housing.
And make sure you bench bleed the MC before installation; buy a short (18") piece of steel brake line, cut it in two & bend it so that when the screw couplings are attached to the suppy & return lines the open ends are submerged in the reservior, pump the MC plunger until the bubbles stop.

_________________
'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

Sometimes in a master cylinder the cups will tear a little and will hold pressure..then release when it is not appropriate, have had this happen twice to me on older vehicles .

sounds about right... hit th brake and it is just lazy. if it has an effect it either grabs and then releases itself and lefts the pressure off the pedal, or will occasionally grab, but give out again while stopped and i will have to hit the pedal another time or two to get it to stop rolling backward or forward.

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

Yea, that's textbook master cylinder symptoms if it's not using fluid. If it's using fluid, (you are seeing fluid disappear from the reservoir) then it could be a wheel cylinder.

_________________
OK, I'm over it. Where's the beer?

fluid hasnt changed moved a bit and nothing leaking from any of my wheel cylinders. called in and i will have a new master cylinder on the 22nd when i get paid

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride