brake fluid problem!!

[CB74dr_Lov3r]

Hi guys!! My name is Xavier and im new here but ive been looking around for some time now and I love the forum. I had DB7 but i sold it to fix my cb ex sedan that I had sitting for like a year . I swap a F22b dohc into the car and i runs great , is an auto but who cares !! My problem is that everytime i put brake fluid into the car starts smoking by the exhaust and also I notice that is leaking fluid between the cylinder and the booster . Does this has anything to do with this?? Any help would be thankful.

[batever]

Hi guys!! My name is Xavier and im new here but ive been looking around for some time now and I love the forum. I had DB7 but i sold it to fix my cb ex sedan that I had sitting for like a year . I swap a F22b dohc into the car and i runs great , is an auto but who cares !! My problem is that everytime i put brake fluid into the car starts smoking by the exhaust and also I notice that is leaking fluid between the cylinder and the booster . Does this has anything to do with this?? Any help would be thankful.

I don't see how the leaking brake fluid is getting onto your exhaust but i guess it's possible and it would definitely smoke. oh, you have the ex and if it has two exhaust pipes that might explain things.

In any case, smoke or not, you need to replace your brake master cylinder and clean off your brake booster before the brake fluid peels the paint off it and starts rusting the booster through and ruining it.

You can get a new brake master cylinder for like $50 at autozone. That and a $10 one man brake bleeding kit and you're good to go.

It's hard to get at the mounting nuts for the master cylinder--break them free with a wrench, then put a flexible spring extension or 6 inch extension plus a universal swivel socket and a 13 or 12mm socket and they will come off and go on fast. The line fittings that feed into the master cylinder use a 10mm wrench, preferably a flare nut wrench because they are pretty soft and a regular wrench might (MIGHT) round them off but a flare nut wrench won't.

You need a 10mm wrench for the four brake bleeder screws. Since you have an ex I believe you won't need an 8mm wrench for the rears although us drum brake people do.

BTW, it's necessary to keep all petroleum products away from the brake master cylinder and its piston and seals. brake fluid is glycol or silicone based, not petroleum based and petroleum products will wreck your brake system if it gets inside by swelling up the seals in the brake system. When you pull the old mc off you may see some greasy stuff where it mounts against the firewall but it's not petroleum grease so don't start greasing anything up.

Good luck!

[YK86]

I think what is happening is the master cylinder is leaking bad enough from the back that it's getting into the brake booster. Since the brake booster runs on vaccum from the motor, the brake fluid may be getting sucked into the engine. This is not unheard of and it makes sense with the situation you describe.

Either way, like suggested, change the master asap. You may also want to grab a new brake booster since one that's soaked in fluid internally may not last long.

[batever]

I think what is happening is the master cylinder is leaking bad enough from the back that it's getting into the brake booster. Since the brake booster runs on vaccum from the motor, the brake fluid may be getting sucked into the engine. This is not unheard of and it makes sense with the situation you describe.

Either way, like suggested, change the master asap. You may also want to grab a new brake booster since one that's soaked in fluid internally may not last long.

Great, great point about the MC leaking INTO the brake booster. I didn't think of that and hadn't heard of it either.

YK86, do you think the same thing could have happened to me? I have a master cylinder that's been badly leaking out the back for a total of one day. I hope that fluid just stayed on the outside of the brake booster and isn't somehow wrecking it. I'm removing it tonight.

OP, there's a vacuum line and a one-way valve from the brake booster to the throttle body or intake manifoldl (i'm not sure which) and that sucks pressure from the brake booster (to put a vacuum into the booster so that it can use that vacuum to assist your brake pedal efforts) duringthe intake strokes of the pistons. If there's brake fluid inside the brake booster itself then that fluid would get sucked into the throttle body and from there go right into the combustion cylinders. Instant smoke.

[CB74dr_Lov3r]

thans guys for your help!! im going to get a new master first to see what happens. and another question. would this will be hurting the engine??

[batever]

thans guys for your help!! im going to get a new master first to see what happens. and another question. would this will be hurting the engine??

Probably not. If you're using standard DOT 3 Honda brake fluid, I looked it up and it's glycol ether based which means the combustion byproducts are basically CO2 and H2O. Besides, the amount we're talking about is very small compared to the amount of gasoline that goes through the cylinders. The white smoke you're seeing is probably water vapor from the breakdown of the brake fluid in combustion.

If it starts getting hard to apply the brake pedal, that means your power booster has lost vacuum and you have lost assist but you can still stop by stomping as hard as you can on the pedal. A simple way to test the booster is to apply the brake with the car off, then start the car with your foot still pressing the brake pedal. Once the engine is runniung, the power assist from the booster will cause the brake pedal to sink down lower if the booster is working.

[red07frontier]

Sounds like the brake fluid is just dripping down and onto the downpipe and burning on the exhaust to me. Just change the master and it will burn off over time. No need to swap out the booster and waste money and time

[batever]

Sounds like the brake fluid is just dripping down and onto the downpipe and burning on the exhaust to me. Just change the master and it will burn off over time. No need to swap out the booster and waste money and time

The OP didn't say where the smoke was coming from.; On my car a leak from the mc wouldn't drip anywhere near the exhaust pipe though, but I don't know about the EX.

OP, if the smoke is coming out the tailpipe, it's from inside the engine. If it's coming out of the engine bay, it's just dripping on something hot like the exhaust.

Agree that not changing the booster unless there's a problem is one of two valid approaches.

[YK86]

Great, great point about the MC leaking INTO the brake booster. I didn't think of that and hadn't heard of it either.

YK86, do you think the same thing could have happened to me? I have a master cylinder that's been badly leaking out the back for a total of one day. I hope that fluid just stayed on the outside of the brake booster and isn't somehow wrecking it. I'm removing it tonight.

I actually don't really have an answer for you. All I can suggest is to check the seal between the master and booster and the general area behind it for excessive fluid and go from there. If your car doesn't smoke like the op's (assuming his is smoking out the tailpipe), then I won't be too worried about it.

If you aren't sure, I would just change it. Actually, I only say that because we have tons of cheap wreckers around here and a good used one is only $15-$20. I'm just one to change something instead of leaving it and being paranoid of if or when it will crap out lol. But if you are in an area where they'd want like $80 for one, then I'd just wait and see.

[CB74dr_Lov3r]

well im my case the smoke is coming out the tailpipe!

[batever]

Xavier, when you remove your master cylinder, easiest way is to

0) suck all the fluid out of the reservoir with a turkey baster
1) remove the reservoir from the top (it will usually come off just by twisting and pulling). This will give your hands a lot more room to work and a lot more wrench room.

3) loosen and remove the two hydraulic fittings from the master cylinder. Use a 10mm flare nut wrench (line fitting wrench) in preference to a normal 10mm wrench, becuase those fittings are soft brass and the extra width/surface working area of the flare nut wrench helps keep them from stripping.

3.5) break both mounting nuts free with a wrench (12mm or 13 mm depending on the nuts there). You can hook the closed end of the second wrench over the open end of the first wrench to get the leverage to break the nuts free, like this:



4) shift the hydraulic lines so you can get a socket on a flex extension onto the mounting nuts of the master cylinder, making your removal time really fast. I threaded mine through both hydraulic lines. The flex extension I used is like an 8 inch long flexible spring that's firm enough to apply some decent torque. It came in very handy on this job. A straight extension might work, too, something around 6 inches long, or perhaps a universal joint extension or wobble extension.

If you can't get a socket onto those nuts it takes a little while using just a wrench. Unless you have a ratcheting 12mm or 13mm wrench, which I don't have and which probably would work even better.

You'll want a magnetic pick up tool to retrieve any dropped washers or nuts.

Keep an eye out for the rubber seal at the back of the master cylinder, which may be stuck onto the master cylinder (pry it out with your finger) or may be stuck to the mounting area of the brake booster. You may need to reuse it if your new master cylinder doesn't come with it.

also, buy a couple extra 8mm diameter X 1.25 mm pitch nuts in case you drop a mounting nut and cant retrieve it.


Out of all three times I have now pulled a brake mc, doing it this way has been the quickest-like 10 minutes or less.

[batever]

I actually don't really have an answer for you. All I can suggest is to check the seal between the master and booster and the general area behind it for excessive fluid and go from there.

I pulled the master cylinder outside in the driveway tonight after I got home (in the dark using a worklight with the crickets sounding all around me!)

The fluid that was leaking out the back looks like it mostly didn't go into the brake booster but I'm sure some got in there, I won't worry too much about it though.

While it was off I got into a very fastidious mood and decided to clean the outside of the booster with 90% rubbing alcohol, then scrape the rust off the brake booster and I Naval Jellied it to get all the rest of the rust off. After rinsing it clean and letting it thoroughly dry I painted the bare area of the brake booster with Hunter Green RustOleum from a can (I don't have any black paint at my house for some reason).. I'll wait till tomorrow night to reinstall the master cylinder and bleed the brakes so the paint will be totally dry.

[YK86]

Haha, I know how that feels (working in the dark and in my case, frogs croaking). I also frequently run in to situations where the paint color I need is the only color I don't have.......

Did you leave the master attached to the lines? It's only for a day but if it gets damp at night, the fluid will probably suck moisture from the open lines.

[batever]

Haha, I know how that feels (working in the dark and in my case, frogs croaking). I also frequently run in to situations where the paint color I need is the only color I don't have.......

Did you leave the master attached to the lines? It's only for a day but if it gets damp at night, the fluid will probably suck moisture from the open lines.

Good point. No, I didn't leave the master attached--I covered the ends of the lines with little "condoms"--fingers I ripped off of one of those blue latex gloves--but I didn't tie them on securely them so water could definitely get absorbed by the fluid.

I may flush the entire system with 100% denatured alcohol (because that will be cheaper than using brake fluid, plus will clean out any petroleum contamination that I was worried about) and then just refill and bleed.

[CB74dr_Lov3r]

Xavier, when you remove your master cylinder, easiest way is to

0) suck all the fluid out of the reservoir with a turkey baster
1) remove the reservoir from the top (it will usually come off just by twisting and pulling). This will give your hands a lot more room to work and a lot more wrench room.

3) loosen and remove the two hydraulic fittings from the master cylinder. Use a 10mm flare nut wrench (line fitting wrench) in preference to a normal 10mm wrench, becuase those fittings are soft brass and the extra width/surface working area of the flare nut wrench helps keep them from stripping.

3.5) break both mounting nuts free with a wrench (12mm or 13 mm depending on the nuts there). You can hook the closed end of the second wrench over the open end of the first wrench to get the leverage to break the nuts free, like this:



4) shift the hydraulic lines so you can get a socket on a flex extension onto the mounting nuts of the master cylinder, making your removal time really fast. I threaded mine through both hydraulic lines. The flex extension I used is like an 8 inch long flexible spring that's firm enough to apply some decent torque. It came in very handy on this job. A straight extension might work, too, something around 6 inches long, or perhaps a universal joint extension or wobble extension.

If you can't get a socket onto those nuts it takes a little while using just a wrench. Unless you have a ratcheting 12mm or 13mm wrench, which I don't have and which probably would work even better.

You'll want a magnetic pick up tool to retrieve any dropped washers or nuts.

Keep an eye out for the rubber seal at the back of the master cylinder, which may be stuck onto the master cylinder (pry it out with your finger) or may be stuck to the mounting area of the brake booster. You may need to reuse it if your new master cylinder doesn't come with it.

also, buy a couple extra 8mm diameter X 1.25 mm pitch nuts in case you drop a mounting nut and cant retrieve it.


Out of all three times I have now pulled a brake mc, doing it this way has been the quickest-like 10 minutes or less.

good info!! thanks!! ill definitely try this way!