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99 disco II - smoking after brake reservoir replacement
hi everyone! I'm new here so I'll try to get down to business. I'm pretty good on most repairs (I've done brakes, replaced the radiator, water pump, hoses, tune ups etc...I'm not a novice...until you read below...eek).
Did the brake reservoir replacement kit...followed the bleeding procedure in the DII workshop manual. Started the car and pumped the breaks a few times...all of the fluid was drained out of the reservoir. So, like a DA, I filled it up and repeated the procedure...twice. Noticed the HUGE cloud of smoke, turned it off and started reading forums. The booster was FULL of fluid and likely the fluid got sucked up by the vacuum line in the booster causing the smoke. Took off the master cylinder and the booster. There was a gasket between the master cylinder and the booster although quite small.
So now for some general questions.
Is there supposed to be ANY brake fluid in the booster? I don't understand the function of the booster. Looks like there is supposed to be fluid in there but I'm just not sure.
I'm guessing since I caught the smoke within about 20 seconds that an oil change would take care of the smoke.
Finally, what the heck do I do now? As i retraced my steps, I don't see anything i did wrong. It has to have something to do with the booster and master cylinder...Help an old disco guy!
When you took out reservoir & put back, you missed or misplaced something, reservoir should not leak into booster,,
And please explain what you mean by changing oil to take care of smoke,? If you mean motor oil is contaminated, just take vaccum line off of booster & start engine to get rid of whatever brake fluid still in manifold, & empty fluid from booster,
burning a little brake fluid won't do harm,,, but engine might like it & get addicted , (they say DOT4 has better high than DOT3) so don't give her any more brake fluid,!,,, Jkn,
Yeah, I did the same thing 4+ years ago. Brake fluid in the booster ruins it. I don't recall the specifics of what I did wrong but you'll need a new (or used) booster. (Not a new master cylinder as Red5 stated above.) I dashed across town before the U-Pull closed that Saturday to get my replacement and it's worked fine, although many people don't like to use used brake parts. I (and you) likely somehow goofed up the O-ring on the back of the master. Your error has nothing to do with your bleeding procedure.
BTW there was someone on the forum last summer who replaced the booster without disconnecting the brake lines from the master cylinder, which saves needing to bleed the brakes. He unclipped the lines from their supports and was able to get enough flex to get the job done. You may decide to pull the master cylinder anyway just to carefully inspect the O-ring.
And as Bom2oo2 says there should be no need for an oil change just because of this brake fluid problem. The brake fluid that leaked into the booster got sucked into the intake via the brake servo vacuum line and was burned up in the engine.
1. booster should be dry
2. the booster is ruined because of the brake fluid...can't it be cleaned out...thoughts?
3. the seal between the master cylinder and the booster is an o-ring between the two...just one skinny o-ring...is this the root cause?
4. no need to replace the master cylinder
5. brake fluid was sucked into the manifold, not the engine so what is burning in from there. no need to change the oil
6. the system is full of air now that everything is removed...it will need to be bled again...lots of stuff on different forums about a computer needed for bleeding. Also, forums also say to start with the farthest tire and work closer yet the manual says right front, left front, RR, LR. thoughts on this also...
1. booster should be dry That's what I wrote.
2. the booster is ruined because of the brake fluid...can't it be cleaned out...thoughts? It might be possible but used boosters are inexpensive and fail rarely so why bother?
3. the seal between the master cylinder and the booster is an o-ring between the two...just one skinny o-ring...is this the root cause? Yep. Be sure to inspect it carefully for damage.
4. no need to replace the master cylinder I don't see why if you just rebuilt it.
5. brake fluid was sucked into the manifold, not the engine so what is burning in from there. no need to change the oil The manifold is part of the engine, as are the combustion chambers where the fuel (and in this case brake fluid) is burned, so it's not correct to say brake fluid was not sucked into the engine. What's important is that it's unlikely enough brake fluid made it through the combustion chambers, past the piston rings and into the oil pan to cause a problem with the oil.
6. the system is full of air now that everything is removed...it will need to be bled again...lots of stuff on different forums about a computer needed for bleeding. Also, forums also say to start with the farthest tire and work closer yet the manual says right front, left front, RR, LR. thoughts on this also... Just follow the brake bleeding instructions in the RAVE. If you don't have a copy of it just ask here. Someone will share a link to the PDF.
mln01...thanks for the input...I've found a used booster and will put it in. just one more QQ...see the picture below...If you can remember from 4 years ago, is the o-ring in the picture located in the correct place. Although this one looks fine, I am going to replace it. I cannot find a single diagram that shows this o-ring. I would be between the booster and the wall of the master cylinder bracket. thanks again and I'll let you know how it ends up!
hi guys! The pain is finally over! I put on the new (used) booster and installed the master cylinder back but heard it dripping in the booster again! It was a seriously a WTF moment. Took everything apart again and the master cylinder was leaking (even with the new rebuild kit). I cleaned out the booster...very little brake fluid in it...bought a used master cylinder, installed it, bled it and everything is good. It did take about 20 mins to burn off the brake fluid that got sucked up by the booster...my neighbors love me.
So my .02 to anyone with this problem...Just buy a new or used master cylinder...more cost effective in the long run!
99 disco II - smoking after brake reservoir replacement
