shaking and smoking

[akessel56]

So what is going on. After the car sits for an extended spell, when I run it for a bit (and not that long) the car starts to shake (the whole thing) then the brakes go soft and smoke comes out from the wheel well.

I let the car sit overnight, and all seems fine now, hasn't repeated.

This has happened twice in last year, and my mechanic of course can't find anything wrong.

What the heck is it?

1971 280 SL

Thanks, Andy

[Benz Dr.]

Possible vacuum leak through the booster? Maybe there's a lot of fluid inside the booster that's getting sucked into the engine causing all of the smoke.
Which side wheel well are you looking at?

[DaveB]

Have you replaced the brake hoses recently? Those signs could be consistent with a restricted hose on one side.

[akessel56]

No I havent messed with brakes is 10 years. I'm thinking brakes for sure.

So I just tell my guy I want to replace the brake hoses front left and right? 

[akessel56]

I should also mention while this was happening I lifted the hood and fluid was squirting out of the break reservoir cap. Didn't even know there was a little whole there.

[Benz Dr.]

Yup, there's a little whole in the cap of the break fluid container.

[twistedtree]

Replacing the brake hoses is a good preventative thing to do, but the symptoms of swollen and blocked hoses would typically be brakes that are dragging.  Could the smoke have been overheated brakes?  I guess that could be the cause of the smoke, and if the brakes got hot enough to boil the fluid that could push it back through the lines and overflow the reservoir.

If the smoke was coming from the exhaust then I'd lean towards fluid in the booster that is getting ingested by the engine.  That would also explain the shake.  I'm otherwise having trouble explaining the shake.  Is the shake while driving, while braking, or while stationary at idle?

[akessel56]

Here is the sequence:
A) Car hasn't been run in 4 months (at all)
B) After driving for around 5 minutes (stop and go) at moderate speed >35 mph the car begins to shake
C) when I stop, i can smell something burning and when I open the hood the smoke seems to be coming out of front right wheel well mostly.
D) noticed the liquid streaming up out of the brake reservoir
E) After letting it sit overnight - I seem to be able to drive it anywhere, no problem doesn' recur.

So I'm leaning to a brake hose issue, its easy to do (for someone who knows how at any rate) and the brakes overheating, and the shaking being the brakes grabbing.

But why does it go away?

I will do the hose thing, doesn't sound like it can hurt, and would be a good preventative.

Thanks!

[Cees Klumper]

Replace the hoses (all 4) for sure. The problem goes away after sitting because the restricted hoses aren't 100% blocked, so they do allow the fluid to slowly return through the hoses. Don't drive the car with potentially defective brakes.

[twistedtree]

And be sure to clean up the spilled brake fluid before it eats through your paint.  The stuff is like blood from the Alien

[ja17]

Yes, most likely bad brake hoses, causing the brakes to stick on.   The smell and the smoke are the over-heated brake pads.  The over-heated brake fluid eventually boils and causes the brake pedal to go soft as fluid expands and  squirts out the cap!

[akessel56]

Can someone help with which parts I need exactly, and where to order from?
There seems to be some variation.  Thanks

[Cees Klumper]

Can someone help with which parts I need exactly, and where to order from?
There seems to be some variation.  Thanks

This is very straightforward and any normal parts supplier should be able to send you the correct parts with minimal instruction: "the brake hoses, front and rear" or something to that effect. That should do it?

[ja17]

There are a total of four rubber brake hoses.  Invest in an 11 mm line wrench before you begin. Yo',ll need new brake fluid and someone to help you bleed the brakes when all is back together.