brake line leaks at rear wheel

how can i fix a leaking rear brake line at the wheel on a 2004 tundra have replaced both wheel cylinders and replaced the rear brake line on the Ps where it's leaking at the back .. of the wheel cyl .need Input or Help FAST putting it in shop Mon for this + inspection witch is due .i have been messing with this since Oct

 

Got any pictures of the leak?

 

The most common cause of a leak is the nut is not fully tight. Could be a burr on the threads misleading you to think it's tight. Are you using a line/tubing wrench on the nut to make sure it's fully tight? Other than that possibly a defective wheel cylinder or bad flare on the line.

 

PCJ ... new rear wheel cyl both sides and brakeline on the ps rear .. i thought i had a defective wheel cyl 1st new1 so replaced again still leaks but the leak didn't start till i replaces new cyl ? .. only reason to replaced the wheel cyl is 1 of the outter boots had a whole ,almost tempted to take the rubber seal's off the new put on the old and see what happens lol but its not funny after 3 months

 

AZTundra no i dont have any pics but i can take a few Wed afternoon

 

Yeah, at this point if your old cylinder is in good shape except for the boot I would just change the boots like you were thinking. I did it many years ago on a different vehicle and it never created a problem and solved my frustrations.

 

So the leak is where the lines meet the wheel cylinder on the backing plate? Does it leak when the truck has been sitting for a while or only after applying the brakes?

 

Something is causing it to leak.
A flared brake line is made to seal itself. Slow down. Find out why it’s not sealing. Did you use the correct thread brake line? Is there garbage on the flare not letting the nut fully tighten against it?
Is that line 100% straight right before it enters the cylinder?
2 brake cylinders.. 1 line. I’d look more closely at the line.

 

Toyota usually has a short steel line into brake calipers, and the rubber flex line connects to steel lines on both ends. What is your config?

Edit: Above is incorrect. Not always true, especially on the rears. My bad. @Scuba is on track imo. I suspect there's a problem with the flex hose or it's installation.

 

It would be a hard line from a T on the axle to both cylinders.

 

leak getting worse Rear P/S brake line was threaded in by hand the tightened with brake line tool so threads are not crossed blew out the wheel cylinder clean no junk & line good filled master cyl after sun went down by 9pm the master cyl had lost 3/4 of the fluid got this truck in 2015 no brake problems like this till Sept 2019 .. Mon the 23rd the truck goes in the shop if i cant get the leak fixed i tightened the line going into the wheel cyl to the point I'm afraid ill strip it

 

The cylinders are cheap. If you strip it trying to stop it leaking its no great loss, it has to get tight enough to seal no matter what. Its a metal on metal seal so it takes a bit of force to deform the end of the brake line enough to form a hard seal so don't be afraid of torque, it takes a lot.

 

Lol yea 1st 2 new wheel cylinders i got from O'Reilly Auto house brand not a import direct fit ,original says Asian stamped on the side Napa has a import direct fit for a 2004 tundra ,but if i get the line so tight that is strips wont that also mess up threds on the line & cylinder?

 

Yes, but what else can you do? If you can't get it to seal with torque your only other option is to replace the line and or the cylinder anyway. Its pretty common to replace the line anyway, its only really designed to seal once, although usually you can get away with reusing it a coupe times.

 

the line in the pic was a new line i had to buy a tube bender only cost about 8$ so that wont brake the bank lol ..

 

You want an OE line from a tundra rear end? May be worth a shot to try it. I’ve got a rear axle sitting in my garage you can have the brake line off of it.

 

What is the part circled below in red? Pic seems to have line connection totally obscured, and the wheel cylinder mostly obscured.

 

ABS sensor.

 

And yes that device is blocking a clear view of said connection at cylinder.

 

Is it possible you have the wrong type of flared brake line? (there's more than one kind)

This page explains the difference: http://www.fedhillusa.com/?page=flare

For what it's worth, the pre-bent tubing from Toyota is remarkably inexpensive. I just bought them for my front brakes, and I think they were $7 each.

 

I agree with this.
https://parts.autonationtoyotasouth...-tundra--sr5--4-7l-v8-gas/brakes--rear-brakes

 

This ^^^^.

If close inspection of the threads and mating connection surfaces provides no obvious clue, and there's nothing touching or obstructing free tightening of the fitting nut, then I think you are going to have to try again with new parts. Or, give up and let the shop fix it and take your money.

I've never had a problem with flared tubing connections leaking, but I can't remember ever having to break a flared fitting on a Toyota (30+ years ownership, 180K miles). Using OEM parts will usually avoid the kind of problems you're experiencing; if you DIY, you'll save more than enough on labor to buy OEM parts. There are three different RH brake tubes for your MY truck (see link below, Item 8, wheel cylinder at bottom of page). Depending on his skill and experience, the counter guy at NAPA may ask which model you have. Aftermarket parts are perfectly acceptable for an older truck imo...if you make sure what they've sold you is exactly the same as what you've removed.

https://parts.toyotaofcoolsprings.com/v-2004-toyota-tundra--sr5--4-7l-v8-gas/brakes--rear-brakes

 

I have the OE brake line that came off of the rear P/S i had just bought a new line but thinking of putting the old line back on & tighten the hell out of it
,gotta go working on it now

 

Since the cylinder and the brake line are both new, I suspect that one of them has a different mating surface for the seal. It looks like you bought a pre-flared line from the auto shop that you bent to shape. Was it the double flare for Asian vehicles? I know this was harder to find at my local shop and they had few options. Also, the guy at the shop was not familiar with them. Was the cylinder for Toyota? If you still have the packaging, or can look up the part number, what type of flare does the cylinder have?

 

Remember, it's not only the threads that need to match, but the flare types as well. I suspect your new parts are not mating properly at the flare.

For example:

 

Wheel cyl was from O Reilly auto parts but i have seen 1 at NAPA that says Asian that is stamped into the casting O Reilly's did not it will get kind of like a universal that would fit that could be the problem still working

 

The 1st one its a flare fit ... pic on the Lt not the bubble on the Rt

 

that's the rear speed sensor 1 on both sides

 

I guess the first question should have been what brand of parts you are using. After all this time and trouble just be done with it and put in OEM parts. That flare fitting seal is not that problematic so there is obviously a defect in the aftermarket parts.

 

does anyone READ go back through what i have done so far I'm getting the same question that have been answered already ..

Dont both me if your going to ask the same question