kesha1

Hi,
I thought that I felt it for some time before I changed the break pads, but afer they were changed something strange started happening to my ML320:
1. After driving for some time releasing the break pedal does not make the car move (i.e. on a stop sign).
2. The rpm and the angine has to work harder to move the car as if some breaks are locking up.
3. Once I tried to force it and drive anyway smoke started coming from under the hood.
I think something similar but on a lower scale was happening before, but after changing the pads it became really dramatic (maybe a coincedance).
The thing is that the mechanic can't see what exactly the problem is untill it accures, but by that time I am pretty far from the mechanic's place.
It doesn't really happen when it's cold.
So, it happens, but only when it's warmer and it might act as the breaks locking up but it did generate a fair ammount of smoke once.
Please let me know what it might be.
Thank you.

Maj. Dundee

When you say I changed the brake pads", does that mean that you yourself changed them or you had them changed?

The smoke that you see is not coming from anything under the hood. It is coming from one of the front wheels. In all probability one of your calipers is locking up and not releasing.

kesha1

No, a local mechanic did it in his shop.
Yes, he suggested that a caliper can cause it, I just don't understand why is it doing when its a hot day and doesn't do when the air temperature is lower, and why did it start after changing the pads, a coincidence?

Maj. Dundee

When you replace brakes, the piston in the caliper is always extended out because of brake wear. To instal the new pads you have to push the piston back in to the caliper to accommodate the new thick pads. Because of this sometimes the caliper gets stuck.

It happens more often in hot weather because metal expands in heat.

kesha1

Thank you, Maj. Dundee,
what's the easiest way to fix it? The same mechanic asked his employee to go through the pads installation once more and they didn't see any problems, so, he asked me to come when the problem accure, but it always happens far from home. Should I simply ask to adjust the caliper, or they are not adjustable and must be replaced?
How would I know which one?

LeviDenim

Before replacing the caliper it would be goo to know if the brake fluid was flushed or bled.
If the fluid is old it can become very sensitive to temp change and needs to be changed.
Only use DOT4+ fluid. I strongly recommend the MB fluid.
If a caliper has gone bad rebuilt units are widely available and not very pricey. Labor is half an hour.
Then the fluid really should be bled at all four calipers on the truck.

Maj. Dundee

Now that you have said that the problem occurs far into the drive it is probably the brake hose, but you should have the brake hose and the caliper replaced at the same time. This will save you going back to the mechanic a second time.

There is no adjustment on the caliper.

kesha1

Thank you for your reply.
How would I know which caliper to replace? There are 4 of them, right?

kesha1

Yes, it takes anywhere between an hour to ..., well not accuring at all, depending on the air temp.
So, you think forcing a locked caliper might have given a smoke?

Maj. Dundee

You originally said that the smoke was coming from under the hood. So it would be safe to say that it would be one of the front two calipers.

Look at both rotors through the openings of the wheels and whichever rotor is blueish in color is the problem caliper. But make sure you change the brake hose as well.

kesha1

Thank you for your reply,
right, it happened once, when I was forcing the car through that "non moving" mode, and the smoke appeared from under the hood.
So, that mechanic simply didn't know that a caliper problem will leave a blueish trace, and asked me to come when the problem accures because of his incompetence, huh?
Or a problem with a caliper not neceserely will leave a trace?

Maj. Dundee

If you say it produced smoke, then the rotor should be blueish in color. Don't forget to have the brake hose replaced as I think that might be the real issue.

kesha1

Happy Thanksgiving everybody!
I didn't do the repair yet, but there are a couple of things I noticed that I hope might isolate the exact problem even better:
1. when I start the engine thist thing in the morning the brake warning light on the dashboard lights up for a few seconds and then turnes off.
2. when I drive slowly I think I hear some squeeky sound (pretty quiet).
Including all the simptoms above what most likely will it be?
Thank you.

Maj. Dundee

This has been going on for three weeks now and it doesn't appear to be a priority with you. The longer you take to look into this the more expensive it will become.

It now seems that the wheel in question has now worn down the brakes and is causing the squeak.

kesha1

Thank you for your reply.
Actually, it was going on for about 3 years now. It was not happening too often and I don't drive that much.
So, that's what should be done to fix it:
1. Change the break fluid (use DOT4+)
2. Replace brake hose and the caliper on the wheel that the rotor got is bluish in color.
It should take care of the problem, right?