Mushy Brakes = long stopping distance

[cpg]

http://www.powerbrake.co.za/downloads/tech_02_bedin.pdf
check this out. On a 80 it is easy to ruin new brakes.

Did you use 100 series pads?

 

[Land Speeder]

Sounds like you have the same problem I have...
I have had mushy brakes since I've owned my 80, 3 years now. Other 80 series owners cringe when they drive my wagon, and likewise when I drive thiers I bang my head on the steering wheel when I apply the brakes.

The only thing I have not changed is the master cylinder and newly weeping LSPV. I will trying to get a new LSPV this weekend and more than likely purchase a MC rebuild kit in the next few weeks.
As of last night a buddy and myself bled mine and his wagons to see if we could get a little better pedal feel but mine did not, pointing to one thing, the MC.

FWIW - My setup within this past year is stainless brake lines from frame to axle, new OEM rubber lines from front axle to caliper, properly adjusted LSPV for J lift, new OEM rotors and pads, new shoes for rear drums.... so that leaves just the MC

Hope my troubleshooting and experience helps

 

[rockclmbr]

Land Speeder -

Thanks for your reply. This sounds very familiar . I will be waiting for your feedback on the MC rebuild. What is invovled in the rebuild? How much for parts versus a new one?

 

[Land Speeder]

Land Speeder -

Thanks for your reply. This sounds very familiar . I will be waiting for your feedback on the MC rebuild. What is invovled in the rebuild? How much for parts versus a new one?

Well I'm slow and it might be a week maybe 3 before I get it rebuilt. I'm picking up the "repair kit" (as they call it) on Monday. It cost me $50 at the local Toyota parts counter. I believe a MC is over $250, call your favorite parts place... mine is the local Toyota because of the BIG dicounts he gives us local TLCA and repeat members.

 

[RavenTai]

When a master cylinder fails the pedal will slowly creep down with steady pressure.

A "bigger" MC will not improve braking, if the new MC has a larger piston pedal force for the same amount of braking will increase, pedal travel will decrease.Think of it like putting a bigger piston under the handle of the bottle jack, you will have to use more effort on the handle to lift the car.

the 80 uses its rear brakes a lot more than other vehicles I have owned, if you MC does not creep down and the booster does not make noise (leaking) I would look at the rig of the LPSV, there is a gauge set that can be purchased to properly rig the LSPV, if you are having braking problems it might be a good investment.

 

[LX_TREME]

I believe a MC is over $250, call your favorite parts place... mine is the local Toyota because of the BIG dicounts he gives us local TLCA and repeat members.

$250.00 for new MC??? Are you sure? They probably gave you wrong price but hey can't beat CDan price

 

[Land Speeder]

$250.00 for new MC??? Are you sure? They probably gave you wrong price but hey can't beat CDan price

I didn't ask my local parts counter because I knew it was more than the repair kit. As for best prices, in my experience and others from my town, NO ONE can beat our local parts counter when he applies our discounts (and I've tried). I don't know or care how he gives us the discounts but it's cheaper than shipping them and they are always here with in 2 days if not earlier. Just our experience, not trying to start anything.

 

[rockclmbr]

I took the 80 to a local mechanic that I've used before and they do decent work. They said the Master Cylinder is definitely bad.

I'll be ordering a new one this week and hopefully put it in this weekend. I don't know how long it has been in bad shape, but I wouldn't want to risk it.

How many have had to replace the Brake Master Cylinder in the 80 series? Seems like they should last longer. What about aftermarket for off-road performance?

 

[cpg]

none here

 

[RavenTai]

What about aftermarket for off-road performance?

You are looking at the wrong end of the brake system for improved performance. And off road is not where you need more braking power. Larger rotors and calipers if carefully chosen (if even available for an 80 series) can help. Can you lock up your tires on dry pavement? (kick in ABS) I can with stock tires. If so there is no more braking available.

The master cylinder is just a pair of pistons. There is nothing to "upgrade" in the MC by itself.

Master cylinders like the rest of the fluid portion of the brake system will last a long time if you keep up on the fluid, keep trash out and change out the fluid regularly as it absorbs water and can cause internal corrosion of brake parts leading to their failure.


abotu 150K here, AFAIK original MC.

 

[rockclmbr]

Unfortunately I don't know much of the history from 0 - 60k miles. I will most likely go with Toyota brand since they usually know what they are doing when designing LC parts.

And NO, I can't lock up ABS on dry pavement. I can on gravel though!

 

[rockclmbr]

On Saturday we installed a new Brake Master Cylinder. Very simple task as long as you keep the paint eating fluid under control.

You will want to crack the 2 brake lines going to the MC before removing the MC, this will keep it stable when loosening them. Also, remove the cap and unplug the electrical connector and discard. Using a syringe, remove as much of the fluid from the reservoir as possible. There is a clamp bracket on teh fron tof the MC holding the throttle cable. Remove this. Then remove the four bolts holding the MC to the brake booster. It should come off easily from there.

The gasket between the MC and booster was in bad shape and I didn't get one with my MC. If you order one, ask for the gasket specifically. I purchased a sheet of gasket material and cut my own this time.

The new MC will need to be bled. Clamp gently in a vise (horizontal) and fill the reservoir so that the fluid is above the interior baffle at least. Take a large phillis screwdriver and pump the MC while gently holding your fingers over the two holes where the brake lines attach. Alternate holes while pumping until air is replaced by fluid.

Reinstallation is the reverse of removal.

The brakes were bled without the engine running immediately afterwards. The first thing I noticed was the pedal was extremely firm (engine off). When the engine was started, the pedal when down to the floor as it did before

After a test drive it still did not stop like intended.

After further research (thanks Alvarorb) the brakes were bled again with the engine running. Why this is different, hopefully someone else will chime in??

Brakes were bleed following: LSPV, rear ps, rear ds, front ps, front ds, LSPV. This time a lot of air came out of the LSPV. Fluid was very clear, however there were some streaks of "white" which concerns me, but no more dark fluid or air.

Second test drive was a huge improvement, but not 100%. I also played with the height of the LSPV which made no difference at this point. There still has to be air in the lines to get the brake pedal to compress so much.

I'll probably try and power/pressure bleed the brakes one more time next week and see if I can get more air out after driving for a couple of days.

 

[Land Speeder]

After further research (thanks Alvarorb) the brakes were bled again with the engine running. Why this is different, hopefully someone else will chime in??

I'd like to know as well. I always have the ignition on, but never have the engine running. I don't think I've ever seen anyone have the engine running. This might be my problem

 

[rockclmbr]

Engine running = ignition on. I would think the brake/ABS system is on and vacuum is building pressure regardless. I could be wrong though...

 

[Rich]

Brake booster is vacuum operated. Needs engine running to maintain vacuum.

 

[Cruiserdrew]

Jasper-New to this thread, but the need for the motor running is something unique to the 80 series. I could never get it to bleed correctly until I did it with the motor on. Then it's pretty easy. You should be able to get acceptable performance from your brakes, but 80 series brakes are not all that great even under optimal conditions. Add big tires and extra weight, and it definitely reminds you it's a truck and not a car. 100 series pads wil improve brake performance a bit.

 

[powderpig]

If installing the new MC, follow the procdure for adjusting the link(in the FSM). If you are not carefull you can put either not enough or too little space(gap) between the brake booster and the MC. Leading to problems on both sides of the spectrum. later robbie

 

[Land Speeder]

Brake booster is vacuum operated. Needs engine running to maintain vacuum.

even on my non-ABS'd system?

 

[rockclmbr]

"it definitely reminds you it's a truck and not a car"

Thanks for the reality check Andy! You can't have everything, and I keep thinking I want "stop on a dime" brakes on a 3 ton vehicle.

Powderpig- Interesting info on "the link" I will look into this and let you know what I find out. I was unaware of this.

 

[Rich]

even on my non-ABS'd system?

ABS or no ABS, vacuum brake booster needs engine running to be able to continue to boost. With engine off after pump or two of the brake pedal the booster no longer contributes.