1997 LX450 Brake Bleeding Woes

[michaelmontero]

Good afternoon,

I’m curious if anyone else has ran into something similar. I have searched on these forums and have seen a couple threads on people having bleeding issues with their 80s.

This last weekend I’ve changed out every rubber brake line, some of the hard lines, deleted ABS, rebuilt all calipers, and put in a new OEM master cylinder (bench bled it before installation). I just spent the last 4 hours of my life bleeding these brakes, when I get to the last caliper, the pedal will feel fantastic. It’ll feel great in the first minute of the test drive and then it’ll just go soft again. I cannot physically see any leaking brake fluid anywhere under the vehicle or in the engine bay. Nothing is wet. But I’ve clearly got a leak somewhere yea?

I’ll bleed all brake calipers in the correct order until it’s nothing but fluid is coming out. No air. The pedal feels fantastic. Then I get to the driver side front caliper and it just seems like non stop air in the system. Thinking maybe the rebuilt calipers are messed up or there’s some air trapped in the master cylinder?

Just at a loss right now, had to step away from the vehicle for today, grab a shower, and crack a few beers open.

Any insight is greatly appreciated, have a great night!

 

[michaelmontero]

Forgot to attach pictures!

 

[michaelmontero]

If this is the wrong away to post the pics I’m sorry lol. First time using this forum

 

[jonheld]

Smear a bit of grease on the threads of the bleeders. This prevents air from getting into the line as you bleed.

Fwiw, I gravity bleed each corner first which allows the caliper to fill before pumping with the pedal.

I've never had an issue bleeding brakes on my FJ80 or LX450 and I've replaced just about every part on both.
I'm old school and have never used a brake bleeding tool. Just a piece of clear tubing into a glass jar. Always works.

 

[michaelmontero]

Smear a bit of grease on the threads of the bleeders. This prevents air from getting into the line as you bleed.

Fwiw, I gravity bleed each corner first which allows the caliper to fill before pumping with the pedal.

I've never had an issue bleeding brakes on my FJ80 or LX450 and I've replaced just about every part on both.
I'm old school and have never used a brake bleeding tool. Just a piece of clear tubing into a glass jar. Always works.

Thank you for the advice. Will do the grease on the bleeder threads next weekend when I tackle the project again. Never thought of this

Yea I’ve never used a brake bleeding tool either. Tube and a jar and a second person at the pedal. Today I was very tempted to go and buy one off Amazon though

 

[ppc]

@michaelmontero , I see no mention to of replacing or bleeding the LSPV but that could cause your symptoms

 

[michaelmontero]

@michaelmontero , I see no mention to of replacing or bleeding the LSPV but that could cause your symptoms

Good point to call out. I deleted it along with the ABS.

 

[ppc]

Exactly how does the pedal go soft?
Complete loss of brakes or does pumping build pressure?
Is the fluid level in the master staying at a constant level?
A loose wheel bearing can cause runout and push pads away from the rotor excessively requiring pumping of the peddle.

 

[michaelmontero]

Exactly how does the pedal go soft?
Complete loss of brakes or does pumping build pressure?
Is the fluid level in the master staying at a constant level?
A loose wheel bearing can cause runout and push pads away from the rotor excessively requiring pumping of the peddle.

Good morning. I’ll bleed the brakes and the pedal will feel hard and normal. I’ll go on a test drive and after braking twice, the pedal will go soft. As of there is air in the system. And I go to bleed it again and there is air in the system. The brakes will engage on the test drive, just the pedal feels spongy. If I slam on the brakes a couple times in a row, the pedal will stiffen up but just go back to be spongy after a couple brakes.

 

[Godwin]

Since you replaced the MC you should check, and if needed, adjust the brake booster push rod. Using this tool is how you check the push rod distance into the MC https://www.cityracerllc.com/products/brake-booster-gauge-for-any-toyota. May or may not be part of why you cannot bleed the system well, but doing this is critical in dialing in the brake system for best performance.

 

[jonheld]

Good morning. I’ll bleed the brakes and the pedal will feel hard and normal. I’ll go on a test drive and after braking twice, the pedal will go soft. As of there is air in the system. And I go to bleed it again and there is air in the system. The brakes will engage on the test drive, just the pedal feels spongy. If I slam on the brakes a couple times in a row, the pedal will stiffen up but just go back to be spongy after a couple brakes.

As mentioned, check wheel bearings.

 

[VPP]

Good afternoon,

I’m curious if anyone else has ran into something similar. I have searched on these forums and have seen a couple threads on people having bleeding issues with their 80s.

This last weekend I’ve changed out every rubber brake line, some of the hard lines, deleted ABS, rebuilt all calipers, and put in a new OEM master cylinder (bench bled it before installation). I just spent the last 4 hours of my life bleeding these brakes, when I get to the last caliper, the pedal will feel fantastic. It’ll feel great in the first minute of the test drive and then it’ll just go soft again. I cannot physically see any leaking brake fluid anywhere under the vehicle or in the engine bay. Nothing is wet. But I’ve clearly got a leak somewhere yea?

I’ll bleed all brake calipers in the correct order until it’s nothing but fluid is coming out. No air. The pedal feels fantastic. Then I get to the driver side front caliper and it just seems like non stop air in the system. Thinking maybe the rebuilt calipers are messed up or there’s some air trapped in the master cylinder?

Just at a loss right now, had to step away from the vehicle for today, grab a shower, and crack a few beers open.

Any insight is greatly appreciated, have a great night!

The unit below your hand looks like a proportion valve, you probably need to reset it if it is. How to Reset Brake Proportioning Valve? | Symptoms, Steps & Testing Guide - https://www.cnbrakecylinder.com/how-to-reset-brake-proportioning-valve/

 

[jonheld]

The unit below your hand looks like a proportion valve,

That's the ABS controller. The LSPV lives under the truck attached to the frame.

 

[mrsleeve]

Weed sprayer converted into a pressure bleeder will fix you right up. I have always gotten great pedal feels from using them. 80 series and the notoriously spongy from the factory GMT800s

 

[MissahPapaJ]

Not to be a elitist but if it says doorman I’d stay far away from it, try a good old fashioned gravity bleed the older Toyotas really enjoy that sort of thing.

 

[jonheld]

^^^^^this^^^^^
Always use OEM parts on things that prevent you from turning the car in front of you into a bottlecap.
It's more important to stop than it is to go.

 

[Batameez]

I saw Dorman and aimed all skepticism there.

 

[michaelmontero]

Not to be a elitist but if it says doorman I’d stay far away from it, try a good old fashioned gravity bleed the older Toyotas really enjoy that sort of thing.

^^^^^this^^^^^
Always use OEM parts on things that prevent you from turning the car in front of you into a bottlecap.
It's more important to stop than it is to go.

I saw Dorman and aimed all skepticism there.

Dang, I guess i deserve the criticism. We use dorman religiously at my job with no issues, but then again my job is "buy the parts for as cheap as possible and get the vehicle tf outta the shop asap"

I tried the grease the bleed fitting threads and have not had any issues since, been daily driving it the last couple days and loving it.

Maybe after my next overseas desert trip I'll buy the correct oem parts and rebuild everything properly. Hopefully the dorman holds up until then

 

[76lcmike]

pinch off each caliper with small needle nose vice grips, test drive. when the problem stops, winner winner chicken dinner.
try that.

 

[MissahPapaJ]

Dang, I guess i deserve the criticism. We use dorman religiously at my job with no issues, but then again my job is "buy the parts for as cheap as possible and get the vehicle tf outta the shop asap"

Do you work for a Danish owned used car dealership WTF