Alright guys,


I replaced my front calipers and hoses along with the master cylinder last week. I bought Dorman speed bleeders and installed them at all four wheels. The back worked flawlessly, but the front ones both were leaking around the threads on both sides. The truck sits overnight and gets about 1 drop of fluid pools around the bottom of each bleeder. I noticed when I first installed the bleeder screws, I could bottom them out by hand and could only turn them 1/16 of a turn with a wrench until hand tight.


The front are Dorman Help! 12707


I am planning on removing the speed bleeders and installing the original bleeders that came with the remaned calipers.


I have some of the following thread sealant.


Permatex 6 ml. (.203 oz.) high temperature tube thread sealant 59214P - Read Reviews on Permatex #59214P


Would it be a good idea to put a little of this on the threads before installing the bleeders? Its made for brakes and hydraulic systems.


I am also planning on picking up a one man bleeder from autozone to bleed the lines.


OEM One man brake bleeder kit 25036 - Read 17 Reviews on OEM #25036


I have a simple question. Do I need to re-bleed the rear brakes once I swap the front bleeders out? My gut feeling says no, because they have 2 different reservoirs in the master cylinder. I just want to confirm.


Also, is there any issue bleeding with the cap installed on the master cylinder? I made a huge mess the first time by only laying a towel over the master cylinder.






Thanks,
Cody

 

If the system has been bled and has no air in it just removing the speed bleeders and installing the stock ones should be all that is needed.


I say this because fluid should weep out when changing the bleeders and no (or vary little) air should get in.


As for the cap on the master yes leave it on when bleeding as the master will spit fluid up & out.
The cap is vented to let air in as fluid goes out.
Dave ----

 

I have never used thread sealant on hydraulic brake fittings but I imagine one could do so if

- The sealant is designed for such use, and
- One avoids contamination of the hydraulic system internals.


The one-man bleeder thing I use the most consists only of a cup with a hose in the bottom that comes up & out the top and ultimately connects to the bleeder screw. Begin with a small puddle of clean brake fluid in the cup, set it on the ground and open the bleeder a bit, then go pump the pedal until the cup is almost full. Tighten, drain, refill master, rinse & repeat until clear fluid comes out.

I'll see if I can find a picture, I think it was a Lisle thing.

You can probably get away with not touching (bleeding) the rear circuit if nothing was touched/opened up there and everything works well.

Yes, it is advised in the docs to replace the cap. Doesn't have to be fastened down, but put it in place to contain the geysers.


EDIT: I think this is the type thing I use the most:

 

Compare your speed bleeders with the ones that came with the calipers. I bet you will find the speed bleeders are too short. When installed, did the wrench flats contact the caliper body? If so, that means the tapered end of the speed bleeder isn't seated inside the caliper.

The taper at the end of the bleeder (stock or speed bleeder) is what forms the seal. The threads only apply the mechanical force to clamp the tapered end of the bleeder against a matching tapered seat in the caliper. When the bleeder (either style) is tightened, zero hydraulic pressure should reach the threads. 100% of the hydraulic pressure should be captured by the metal-on-metal seal at the tapered tip of the bleeder.

If any pressure is reaching the threads, it means the tip of the bleeder isn't seating properly. The threads provide zero sealing action for normal (bleeder closed) operation. It might seem a little confusing because speed bleeders have sealant on the threads, but that's only to prevent air from getting sucked back in during bleeding.

If the speed bleeders are the same length as the original bleeders, you will have to figure out why they didn't seal or the stock bleeders might leak, too.. Maybe you've got some debris trapped on the tapered seat. But since both front bleeders were leaking, I suspect the speed bleeders are too short.

For the thread sealant you mentioned, it's not needed at all. If it's the type that hardens like an adhesive, definitely don't use it. That would make it nearly impossible to loosen the bleeders in the future. If it stays soft, i guess it would be okay to keep the threads from sticking, but personally I used regular anti-seize for that. Just be careful not to use too much so it doesn't get inside the caliper.

FWIW, I have speed bleeders on most of my vehicles and love them.

 

When you leave the cap in place, fill the master reservoir up and make sure the rubber thing in the master cylinder cap is pushed up flat against the bottom of the cap. The cap doesn't let air in contact with the brake fluid, it does let air in between the rubber and the bottom of the metal cap. So if you use a lot of fluid doing it this way, when you take the cap off you may find the rubber has extended down away from the cap. You need to push this back up and add the fluid you lost.

 

The origional bleeders are the same length as the speed bleeders. There is about 1/4" of threads left hanging out once the bleeder is tight. I stopped by harbor freight and picked up a vacuum bleeder this afternoon. I plan on trying to replace the bleeders tonight when I get a chance. I believe I'm going to try and use some silver anti-seize on the threads of the bleeders that came with the calipers.

Thanks everyone for the advise.
Cody

 

Not to burst your bubble, but I've never been too impressed with vacuum bleeders. In theory they should work fine, but in practice they never seem to get that last bit of air. I've tried them multiple times and have always had to finish up with the Michael Jackson method to get a consistent firm pedal.

I think it's a combination of two things. Pulling a slight vacuum inside the brake system causes any trapped air to expand and aerate, almost like a foam. And then air tends to get sucked in via the threads when the bleeder is open. I've tried adding sealer on the threads (like speed bleeders) but it didn't make much difference. In all cases, after getting a so-so pedal with a vacuum bleeder, the next day (after the foam settled?), I'd get a firm pedal with regular bleeding.

I know it's a pain getting a helper to assist, but I've had much better results that way instead of vacuum bleeding. Anybody else run into the same thing?

 

I figured that might be the case. The vacuum bleeder kit I got looks like it can be used just like a one man bleeder as well. I plan pulling a vacuum on the bleeder valve to pull most of the air out. I will then remove the hand vacuum pump to use the container and hose as a one man bleeder. This "should" get all the air out. I may drive it for a few days and do it one final time just to make sure.

Thanks,
Cody

 

If you think about it, the cup seals in the wheel cylinders are made to seal under pressure, not vacuum. It would probably be very easy to pull air in around the wheel cylinder seals if a vacuum were applied to the wheel cylinder itself. Not sure about the calipers and how it's seal would react to vacuum.

 

Thats a good point. I may just use it as a one man bleeder.

 

Vacuum / air or water follows the path of least resistance.



It would be harder to pull air thru the wheel cly seals, unless they are bad and bleeding would not help in that case, than fluid/air from the master.


BTW I have a Snap-on vacuum bleeder (bought used) that uses shop air to make vacuum.
I used it to bleed the rear system on my 02 Durango when I did wheel cly. worked great.
Dave ----

 

Getting everyone's feedback makes it hard to decide what to do.

I have the the tools to do the job either way.

 

What's the worst that could happen? Try the vacuum method and see what you think. I've only had fair results but others have been fine. If not happy, let it sit a day and try the old-fashioned pressure method.

 

I think why the vacuum tool does not work (great) is it pulls air thru the bleeder threads, remember least resistance, and not from the brake system.


My Snap-on works because it pulls a deeper and more cfm's than the hand held jobs.


I have also used gravity to bleed a new, never filled system.
Fill the master and leave the bleeders open. May take a day or 2 then do the 2 person bleed to finish it off.
Dave ----

 

Well the vacuum pump was a flop. As many of you said, it just sucked air from around the threads. I wound up disconnecting it and using it as a one man bleeder.


Took it for a test drive and the petal felt pretty good, but could use a little more work. When i got back the drivers side was still leaking a small amount.


I am going to call napa tomorrow and get them to order me another caliper. The drivers side stopped leaking as far as I can tell.


Thanks,
Cody