Brake fade but no fluid loss

Hey guys and girls. So, I have come across a problem with my brakes. I upgraded my brakes on my '96 3.4l Tacoma 4x4. I installed the 1st gen tundra calipers, rotors and pads. When im pressing the pedal, I can sometimes push it all the way to the floor and it barely catches. I have no fluid loss either. Its been about 1 year since I replaced my brakes. I don't overuse my brakes or am not hard on them hardly ever. If anyone has suggestions as to what could be my problem, I would very much appreciate it. Thanks in advance.

 

Done a through bleeding of the system to purge ALL the air out? It can take a lot longer then you might think to get it all out of the lines.

 

Air bubble? Try bleeding the lines again.
Flex lines in good condition? If they're old rubber, could they be expanding under pressure?

 

Chech your rear brakes and see if the adjuster is still in there right

 

I noticed I had fluid around the axle seal on my left rear. So going to replace that.

I thought about bleeding the lines again. When we did it the first time they were good up till two days ago. Been fine for almost a year or so.

Ill check the lines more, but like I just stated above, it just started all of a sudden.

Anything else possibly?

 

Air in the lines. If you found a leak, there's air. Bleed again. I've read the tundra upgrade also doesn't do so well with the stock lines. SS brake lines work better

 

Could also be a collapsed brake line feel for soft spots in the rubber

 

Master cylinder internal failure, bypassing fluid.

If you'll try bleeding the brakes again, I'll bet you'll have an almost impossible task using the 2 person pedal method. That will be another indicator of a failed master.

If you do install a new master, remember to bench bleed it before installing.

 

Ill check for the lines. Won't be till after I get off in bout 7 hours. How much do those SS lines go for? If anyone has a price or place I can find them?

 

Yea, my dad thinks its prob the master but we couldn't get into it too much last night cause of the fading light. Thanks guy, ill post later today or tomorrow when we look at those few things tomorrow.

 

Like 40 bucks maybe. Wheelers off-road has a set

 

Thanks, guys. Oh, and I didn't mention this. I have 396k on the truck and im pretty sure the master has never been replaced..... nor have many other parts.

 

I have been using the stock rubber lines with my Tundra brakes with no problems. I have noticed that excessive pedal play can be attributed to poorly adjusted rear brakes. There is a star wheel on the rear of the drum that you can adjust, but it's easier to remove the drum and check it that way. The drum should have a slight grinding or "catch" while spinning, in other words the drums should not spin totally freely, in order to be adjusted properly.

Since you have that many miles it would be worth it to check out the master, but adjusting the drums is free so try that first.

 

When you put on the tundra calipers, did you lose a lot of fluid out of the lines in the process? When I put on my tundra brakes I tried to keep the fluid loss to a minimum but I'm pretty sure it dropped too low in the master cylinder. After a few weeks of driving I was experiencing the same pedal to the floor that you are. It got worse and worse and eventually every time I stopped it dropped to the floor. My theory is the fluid level dropping allowed some crud to get in to the master and mess up the seals. I put in a new master cylinder (bench bled it first), and I was good to go.

 

I made sure not to push the pedal all the way in when bleeding, apparently there is a delicate o-ring in the cylinder that can get messed up if you push too far down on the pedal. When I did my tundra brakes I bled all of the lines, even the back, since it was due for it anyways. Need to get around to doing the clutch cylinder now.

Yes, when swapping calipers and the lines are open (meaning you're slowly losing fluid while you do the job), you really need to keep an eye on the reservoir and make sure it doesn't get low. Keep topping it off. If you don't, you could run into the problems you described, and get more unecessary air in the lines, and at the beginning of the whole line too, meaning you'll have to bleed a shit load of fluid out just to get the air out that you introduced into the system through the reservoir.

 

Well, come to find out, my left rear drum had lots of fluid in it. I think it was from my bad axel seal. Going to replace that and go from there. But I don't think that's what messed up my pedal... I don't know. And when I bled my lines I don't think I lost too much or let air in. Ill try to re-bleed them just for the hell of it. I appreciate all the suggestions.

 

Sure it's not a leaking rear brake cylinder?

 

Should be able to tell from the smell. Gear fluid doesn't really smell like brake fluid.

 

No, it smells like ass lol

 

We changed out my driver rear axel seal and master cylinder. Should be good now.