Hi guys,
I have an issue with my 1996 850 and me and my mechanic are unable to figure out what's wrong. I've replaced pretty much everything in my suspension recently and this issue started a few months after that process.
Whenever I brake at about 60 mph, the car shakes violently. It's fine when accelerating and will only do it when braking at certain speeds. What could be causing this?
I don't know if this info will help but it started after hurricane Harvey. My car was at the mechanics (where else would it be lol) at the time and he says it did not flood. I have no reason not to believe him... It looked fine. However, even though water didn't get inside, maybe part of the suspension was soaked for a while? I also started getting these check engine lights for misfires after the hurricane but they have gone away. My mechanic believes that it could've been due to gas that got water in it and that a lot of his clients were having the same issue.
Any help is appreciated, he says he has looked over all his work and had the tires rotated and balanced... He thinks it maybe the steering box? I just spent over 10k on this stupid car redoing everything and I just want it work
Any help is much appreciated!
Edit: Also, it only seems to start doing it after the car has warmed up a little bit. If it's been sitting and I take it out, it'll be fine the first few times I try it and then seems to progressively get worse until it's shaking quite ferociously.
Last edited by Guts1200; 12-29-2017 at 09:29 PM.
Check the run out of the brake rotors.
Check the brake calipers for binding. Salt water and metal don't get along.
'93 850Ci - Mineralweiß Metallic
2001 740iL - Titansilber
ALPINA B7 -Alpinweiß III
...the price of cool ain't cheap!
Absolutely!
My issue at those speeds years ago were Upper control arms, Change them both, Buy them complete. I chose Lemforder.
Have a read of this ... it covers almost all the likely culprits ... Timm is pretty much a guru on these things ... ( as you may guess from his website)
http://www.meeknet.co.uk/e31/E31_Shimmy.htm
Good luck
If you have non factory brake parts that's why, after you replace the brakes with factory parts then thrust bushings could be worn out from the shaking they we're trying to control
As TxGR8White says - that's a sticky caliper!
Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i
My BMW Repair YouTube Channel
My Current 840ci Sport Individual
My Current 650ci Sport Individual
My E31 Repair and Information Website
My E38 Repair and Information Website
My E63/E64 Repair and Information Website
Chase - Heroes to a generation
My 840 shaked very bad when braking at high speeds, i was convinced it was control arms. I first replaced all my rotors and that turned out to be the problem. No more shaking at any speed.
control arms are the #1 suspects
bad Brake master cylinder causes caliper lockups too... strange, but true
'91 Dinan 860 Stage III (new 6L engine)
'91 Dinan 850 TT stage III (brand new engine) 21st Century Tech meets 18th Century Dinan...
'91 850i 6sp (mint) (sold)
'90 Dinan 750iL TT stage III (Guido - The Beast)
'94 850 CSi The Detroit Auto Show car (restored to factory perfect) (sold)
'96 850Ci, The George Carlin car
''73 3.0 csi, '08 535i, '03 X5 4.6is
...and a few other non BMW cars
Control arms will cause shaking regardless if speeding up or braking. The OP's problem is under braking conditions. Seeing as how the car is in Houston, and the mechanic swears it didn't sit in flood water, I suspect that it did - at least up to the brake calipers. It doesn't take long for those sitting in water, that you will see problems.
Last edited by TxGR8White; 12-31-2017 at 12:42 AM.
'93 850Ci - Mineralweiß Metallic
2001 740iL - Titansilber
ALPINA B7 -Alpinweiß III
...the price of cool ain't cheap!
Had a similar problem. Crazy shake upon braking at speed. Turned out to be rotors and poorly made hub rings on 5 series wheels. Changed to correct hub sized wheels with new rotors and fixed for now.
My suspicions are that your calipers are corroded internally, as often happens with the Brembo units, and so they are sticking. This can lead to pads that don’t retract, and so they overheat, and leave smears on the rotors. Another possibility is that the flex lines to the calipers are damaged internally, and as such keeping the pressure inside the calipers. This rarely happens on both sides at the same time, and leads to the car pulling to one side or the other. Master cylinder problems can also cause the pads to remain in contact with the discs, and then overheat, pad smear, and shake. I would start with the calipers, and if they are free moving, move on to the master cylinder replacement. You will have to bite the bullet on this one, as you have a late model car. The early ones up to 94 can use the 750il ones. I hope this helps. Your mechanic should be able to track this down, or perhaps you need to find a new one. If the rotors are badly smeared / overheated, you will need new ones, as turning won’t help. Of course, an inspection of the traction arm bushings, and ball joints are in order. Turner sells monoball units to replace the rubber units, as does Moosehead engineering. Good luck
Thank you *so* much for all the replies guys! You all are amazing!
I'm going to have him check out the calipers... that sounds like it could be it, especially since it started after the flood. When I test drove it a couple days ago, they were quite loud when braking. Like they were making sounds when closing and opening.
However, if it is the calipers, why would it only do it at certain speeds? Braking under 60 mph seems to be fine but as soon as I go over, it'll do the shake... albeit not always and sometimes worse than others.
The BMW suspension system has a resonant frequency - 50 MPH - 60 MPH for the front and over 80 MPH for the rear:
"If an imbalance is detected, note the speed range in which it arises. The following rule applies for BMW vehicles:Vehicle speed = 80 - 100 km/h Front axle affectedVehicle speed = 140 - 160 km/h Rear axle affected"
From:
http://www.meeknet.co.uk/e31/Timms_b...20Problems.pdf
Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i
My BMW Repair YouTube Channel
My Current 840ci Sport Individual
My Current 650ci Sport Individual
My E31 Repair and Information Website
My E38 Repair and Information Website
My E63/E64 Repair and Information Website
Chase - Heroes to a generation
Hey guys, sorry for taking so long to post, it's been hectic around here.
I've attached a pdf of the suspension work I had done. Everything was working great until the flood...
I asked my mechanic to look at the calipers... need to follow up with him.
"Everything was working great until the flood..."
Oh...No!!!
Very possible the rotors rusted under the pads during the flood, which is not good. If you look closely you may still see a pad imprint on the rotors, maybe not.
The easy way to check for a seized caliper is to drive the car until the brakes shake then drive it for several miles without using the brakes hard, then coast to a stop and feel for unevenly heated rotors. Laser thermometer is a good tool if you have one, if not be careful not to burn your fingers.
If all the rotors are fairly cool and the heat is even at all rotors, you could try to re-bed the pads on the rotors but most likely you will need to replace the rotors. Insurance may pay for the rotors replacement as flood damage.
That is, whenever the rotors get wet under the pads and the rotors are not dried off quickly the rotors will develop a deep rust due the the pads trapping the moisture against the rotors on both sides of the rotor (this can also occur when you wash the wheels and don't dry the rotors off by driving the car).
At a minimum, the rusting under the pads will strip the bedding off the rotors and that will cause the rotors to have an uneven friction spot at the point where the rotors once had a rust spot.
Hence the vibration during hard braking. Measuring the rotors will not show any abnormal run-out or parallelism problem as this is an uneven friction issue.
You can try to re-bed the pads by driving and heating the rotors and pads by stopping several times hard, until the rotors get very hot (slight fade), then continue to drive to let them cool down some and heat them up again to to a slight fade to transfer some of the brake pad material onto the rotors, then keep driving until the rotors cool down and see if the vibration is gone.
However, I don't think you'll be happy until you have new pads and rotors installed.
Last edited by m6bigdog; 01-14-2018 at 02:43 AM.
I looked through your service receipt Guts. Wow . . . $10k! You practically rebuilt the entire car. For that kind of money, I'd hope they would be taking better care of you. I'd bring it back to the mechanic and say, "This is on you." If they are good mechanics, they should be able to figure this one out instead of you having to ask for a diagnosis on the forums.
When something is beyond my technical capabilities, I take my cars to a small independent shop here in Montgomery. If anything is wrong after the work is complete, I bring it in (with no appointment needed) and they take as long as required to get it right without charging me a thing.
Sean
I have had my steering column tightened twice now. Not related?
New rotors are an annual event when I flush the brake lines. The Bosch have a lifetime warranty so it's just a time factor. I'm sure better rotors would last longer but for what cost?
Annual? Are you driving 50k miles a year or something?
Cheap rotors.
Hey guys, quick update:
My mechanic replaced the brake rotors in the front and he says it's reduced the vibration but not eliminated it. He is convinced it cannot be the calipers and says the brakes in the back cannot cause vibrations in the front. He wants to check/change the hubcentric rings (I think that's what he called it?) next... what do you guys think?
If changing the front rotors helped, maybe doing the backs would fix it or is he right about that not being it?
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