On a Nissan PU, the wheel furthest from the master cylinder is the LR, not the RR. The brake lines cross from the drivers side to the passenger side under the hood, run to the back along the passengers side where they split and go to the wheels. At least it is on mine.
I doubt your booster is bad too. Nor do I think you need a new proportioning valve, they don’t seem to ever go bad. Do you have ABS or rear ABS? Again, I would suggest looking at the front pads to make sure that something isn’t forcing the pads back away from the rotor too far. You might need to get a caliper hardware kit for the front calipers, that the stainless steel clips and slides the pads run on. I had to replace them on my 97 when I did my last brake job a couple of weeks ago, and mine is 9 years newer than yours.
Well everybody it was the brake booster. The mechanic bled the brakes first and still said the brakes weren’t working. Told me it was the booster. EVERYTHING was telling me it wasn’t the booster but this is a good mechanic and has taken good care of my wife when I wasn’t around. So I bought the brake booster, he installed it, and I had brakes again. The rears needed some slight adjustment, and another bleed and the brake test showed a slight difference in brake bias in the rear.
So all is fixed, truck passed the crazy military inspection.
Thank you for letting us know the results, but I hope nobody takes the “this is a good mechanic and has taken care of my wife when I wasn’t around” statement too literally.
STOP!!!Don’t buy a booster or any of that other stuff. Take the m/cyl OFF the truck and bench bleed the m/cyl while it is held in a vise, THAT WAY IT IS IN A HORIZONTAL POSITIION and bench bleeding will remove air from it.
May I step in :)…. 2000 Tahoe(old body style) front disc, rear drums… Replaced rear shoes and cylinders, replaced front calipers and pads,rotors… took it to a shop to have it bled they said master cylinder is bad so they replaced it plus the booster, still no pedal so I took it to the chevy dealer they also replaced the master cylinder and tested everything on the brake system and still no pedal. but said the abs is bad…they gave up and refunded my money and said sorry we don’t know… so i removed the abs unit myself and piped the brakes in directly… had a mechanic bleed system still no pedal… anyone want a free Tahoe ? thank you
If the rear shoes were not adjusted properly, you won’t have pedal. They can be self adjusted by applying and releasing the parking brake repeadly until the parking brake is firm, but sometimes if the starwheel hasn’t been moved first with an adjustment tool, the self adjust won’t work.
thank you, rear cylinders and shoes were replaced and adjusted… I tried your suggestion with the E-Brake… still spongy and pedal almost to the floor… now when truck isn’t running the pedal is hard but when its started it goes south lol
Is anyone who is bleeding the brakes using a pressurized bleeder or are they using the two man procedure? A pressure bleed can make all the difference.
Also are you loosing any brake fluid? Even a tiny amount could be due to a pinhole leak in on of the hard lines that is letting in air.
I agree . . . that’s the professional way to do it, in my opinion
At work, I have my own pressure brake bleeder and all the adapters, so that I can literally bleed brakes on all of the vehicles at my particular location
I can get rid of all the air and force through new fluid . . . without having to pull another mechanic off his job.
Brake fluid is incompressible so has to be going somewhere it shouldn’t when you step on the brake pedal. It’s just a matter of finding out where. Try clamping off the flexible brake lines one at a time, you might be able to narrow down which circuit it is that way. There are specialized clamps you can buy for this purpose, but I don’t know what they are called. I’ve seen them at Harbor Freight. One thing you should check before doing anything else is making sure the calipers haven’t been installed left/right reversed. Believe it or not it is possible to do that, and it isn’t an uncommon reason for this symptom. Check the condition of the flexible brake hoses at the same time, and those going soft can cause this. The caliper bleeder screws must be pointed upward, not downward. You might want to re-post your problem as a new topic btw, if you can’t resolve it quickly.
Thank you, Its been pressure bled and manual bled several times. Its not losing fluid at all. Bleeders are on top. Hoses seem fine. I will verify the Left/right positions…
I would readjust the rear brakes again, moving the shoes out until it is difficult to turn the wheel and then incrementally releasing the shoes inward until they lightly scuff the drums.
Hi Keith and thank you, yes there using power bleed and manual bleed both… no leaks and no fluid is lost… I know this doesn’t seem possible but even the chevy dealer gave up on me… The chevy dealer said they even pressurized the entire system and even removed the front calipers to inspect. I have had 4 different shops attempt and they all have had no success. I will suggest to have the “current” mechanic replace the rubber hoses.
There may be one more thing that has been overlooked, especially if you replaced either the booster or master cylinder and that is the clearance between the push rod of the booster and the socket of the master cylinder. If the clearance is too great, you can get the soft pedal. If it is not enough, then the brakes apply themselves but you certainly don’t have that problem.
It requires specialized tools to make this measurement but I have done it with some kids play dough or other clay. Plastigage might work for this as well.
Yeah actually because too great a gap causes low pedal when the vacuum is applied, not necessarily a soft pedal. But when you have gone to the end of the run, it can feel soft too.
