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.