Brake Bleeding Issue: Possible Kinked Line? SOLVED

SOLVED: tied up the LSPV and bled the brakes with two people.

So there’s a little backstory on this as usual. I just replaced my rear axle this weekend and obviously had all the rear brake lines disconnected. In my stupidity and tired state removing the axle I tried to take off the rear soft line without undoing the connection to the LSPV. This resulted in me getting it lose a few turns and pretty severely twisting and coiling the line. Logic finally kicked in and I decided this was a bad idea, so I wrestled with the hard line and finally got that one off.

Fast forward a few hours, new axle is in, everything’s torqued down and I’m ready to bleed the brakes. Bled the both the rears started at passenger side. I was getting very very little fluid coming out. Finished bleeding the rear and then tested them out. Nope didn’t work, pedal goes down about halfway before biting. Tried again this time I bled the LSPV as well. Got some bubbles out of there but very little fluid coming from rear wheel cylinders still. Tried going for a drive, slightly better, but still not biting like it should. Come back and remember, oh, I probably should’ve bled the fronts as well. Did that and got some little bubbles but not much. This helped some but the pedal still doesn’t feel right. If I am driving slow and hit the brakes it’ll go down about halfway before engaging. However, if I pump the brakes, as you would with non ABS, it builds more pressure and brakes more firmly.

My initial thoughts were brake booster but I can hear the revs go up slightly when I really hit the brakes or pump them. And when the engine is off I can pump the pedal until it is firm, and it stays firm until I start the truck.

My next thoughts were as follows. Repeatedly twisting that soft line slightly kinked or collapsed it (SS braided extended line bought from a TW member that makes them). When I pump the brakes and build some more pressure while driving this opens up that restriction some and allows it to brake more normally.

Does anyone have any thoughts, input, criticisms or experience with this?

note: I’m using a motive power bleeder at 6PSI and fresh dot 3 brake fluid. I bled the rears until I got fresh fluid. I’m out of dot 3 now so I’ll bleed all four and LSPV one more time once I get more.

 

Make sure you raise the arm on the LSPV to get fluid to the back. If your LSPV is old there is a chance it’s seized and not actually doing anything to let fluid past.

 

I’ll try that. Never had problems with rear brakes, just replaced everything including wheel cylinders a year ago. Bled just fine then.

 

If you are actually getting fluid out at the passenger rear then your LSPV is probably fine.

If you think you messed up the soft line, it doesn’t hurt to upgrade to a longer braided stainless line. Even if that’s not the problem it’s an easy and relatively cheap upgrade.

 

Already have a SS extended line back there :/ that’s why I’m hoping I didn’t mess it up

 

How bad is the SS line? Pics?

 

I’ll take a pic tomorrow, it looks fine though. I was worried the inner brake line inside the SS wrap got partially collapsed or kinked. I’ve heard of similar things happening to fuel lines on two stroke jetskis and boats. I also read a couple old threads on TTORA and T4R about people damaging their soft lines and having weird braking/bleeding issues.

My mechanic friend suggested readjusting the rear drums even though I didn’t mess with them. Also gonna rebleed.

 

Seems like it would be worth a shot. I had the passenger rear drum off for a weekend while working on the axle, and had to adjust the brake on that side to get the drum back on.

 

There's probably a lot of air in the lines still. Bleed the LSPV first til you get a clear stream, then try the back passenger again.

 

More bleeding should work, unless your stainless line is still twisted or loose? Take it a off and check it out amd put it back onif it looos ok.

 

My bet is that there is still trapped air. Bleed the LSPV first, the passenger side wheel and the driver's side wheel.

 

Thanks guys I’ll try bleeding again

 

did you let the brake master cylinder go dry? If so you might have to crack the lines loose one at a time, hold a rag to catch the fluid and have a buddy press on the brake pedal then tighten the line at the bottom of the stroke, just to be sure.

 

Nope, master was fine. Not much leaked out at the lspv while I had it disconnected. My power bleeder also maintains the fluid level so it’s not an issue.

like I said, I’ve bled and flushed the brakes on this truck countless times with no issues. Both using the one man method, two man method, and power bleeder. This one has me a bit stumped. Gonna tie up the LSPV after work and try the two man method. Maybe that’ll finally do it.

 

PITA when a "simple" job turns to poo... If it was me, and it has been in the past, I would disconnect the lines on the LSPV if possible and check volume one at a time until the issue is found. I have gone through a brake system trying to figure out why the darn wheel cylinders just wont bleed only to find that some "smutz" had plugged the bleed screw hole from the evening repair to the morning repair. I pull those out completly now and verify that the holes/passages are clear. Crossing my fingers that that is all it is for you.

 

Update: solved it

tied up the LSPV arm then had my buddy pump the brakes while I bled them. Got a good bit of bubbles out of the rear cylinders. Brakes feel much better now. Also adjusted the drums and lubed the parking brake bell cranks. I realized I was running my power bleeder at too low of a pressure. I was doing about 4-5PSI. I remembered that in the past I’ve done 10PSI.

 

I do mine in my other car at 15psi. But I usually do the two person method to "check my work".

 

Interesting. If you want share your input/experience on this thread:
https://www.tacomaworld.com/threads/motive-power-brake-bleeder.685032/

Because there was some disagreement over pressure a while back.

 

Yeah 15psi is the limit. You could damage something if you go over, or so I hear.