Member
Front End Shimmy
Hi ~ I seem to keep having a issue with my drivers side front brake caliper locking on my 05' 325ci. It locked and was replaced about 2 years ago, then about 6 months ago, the front end started the vibrating again. My mechanic replaced it again free of charge since apparently the part was still under warranty.
My question/questions is: is this just a fluke having 2 calipers lock on the same side in such a short time, or could there be something causing this that I need to check? My other concern is that each time the calipers locked, they didn't turn or replace the rotor.
Could not replacing the rotor the first time have caused the caliper to lock again the 2nd time? Also, I now have a slight shimmy in the front end which at times becomes worse when braking. This definitely makes me think the rotor is warped and needs replaced, which I plan to do this weekend.
Can anyone recommend a brand and type of rotors? Id like to find some that don't squeal the first time you use them after it rains. After used once, the brakes don't make a sound until it rains again or they get wet, and then sit without use for awhile. They have done this for years, which is very annoying. I have fairly new brakes and did check, and have lots of pad left, so its not that.
Any advice or recommendations would be greatly appreciated!
Fast
The brake hose going to that caliper should have been replaced. They create blockages as they age and can make a caliper not retract. As for rotors, stick with coated. Pagid, ATE, and OEM BMW are great. Same for pads.
Member
Not replacing the rotor has nothing to do with the caliper acting up. I find it hard to believe that the brake hose is culprit as BMW uses very high quality brake parts. However, your brake hose could be a fluke and is failing. The other issue could be the pins on which the caliper slides. They need to clean and WITHOUT lubricant. The caliper “holes” in which the pins reside need to be clean also. CRC Brake Clean works wonders.
Fast
Hoses go bad no matter the manufacturer. Especially when we're talking about a 12+ year old car. Not saying this is the case, but its highly likely given the reoccurance.
My '00 and '04 both needed all 4 hoses to be replaced when I bought them due to severe cracking. They were daily drivers before I acquired them. My '05 F150 had to have both front hoses replaced due to collapsing.
Member
shimmy likely isn't about the rotors, there are numerous other suspects.
One - tires unbalanced
two- rim not circular (dented)
three - brake hose, as above
four - bad suspension bushings
and many more. But warped rotors - no. The real problem with rotors is that they get "gummed up" unevenly with brake pad material that transfers to the surface during light to moderate braking, causing the coefficient of friction to vary around the rotor. SOMETIMES, you can modify this by doing maybe five or six HARD stops from speed, to heat the rotors and adhered material and spread it more evenly, or cause the pads to scrub it off. The rotors should get nearly smoking hot. Be careful and make sure there's no one behind you who will get in your back seat when you do this. You should get a strong hot brake fluid smell and may decide to flush your brake fluid, which would probably be a good thing. You'll learn about brake fade, too, particularly if you haven't changed fluid at the recommended two-year intervals.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
Member
Actually the garage changed the brake fluid a few months back during the last caliper lock. I plan on replacing the brake hoses and checking the caliper pins as suggested above. I have 194,000 miles and fairly confident the rotors are the original ones that came on the car.
In reading through the forums, I was under the impression the rotors should be turned or replaced with at least every 2 brake pad replacements. Is that not accurate, or more a matter of personal opinion?
So do you think I should eliminate other possibilities first, and leave the rotors as a last resort?
Also, by bad suspension bushings do you mean the control arm bushings, or are there other bushings I should check also? I did replace the sway bar links a few years back, but I think that's all that's been replaced in the front end.
Fast
Rotors are to be replaced when they no longer meet minimum thickness specs or when they pulse. I do not believe in machining them past a certain point and only do it to get a new surface when replacing the pads if they still meet specs and arent pulsing.
Tie rods, ball joints(control arms), control arm bushings, struts, steering shaft coupling, and strut mounts are all wear points in the front end that sould be monitored for wear and replaced.
What part of Missouri are you in?
Member
I'm in southwest Missouri, in the Springfield/Branson area.
Member
My front shakes upon braking on a down-ramp off a 65mph hi-way...but yet too subtle to feel shaking around town...so I ignore it!
Yes, I know I need all new pads, new rotors, and bleed the old fluid..it's on my list of many at 122k................I suspect you may have similar 'maintenance issues' well over due!
Member
Let's look at the issue of turning rotors a little more carefully. Turn them when:
1) they are below spec thickness.
2) when the remaining thickness will wear below spec before you expect to next replace the pads. No point in using rotors that will wear out before the pads; do not put new rotors on with old pads.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
Member
It was in the past a normal thing for Americans to have rotors and or drums "turned" in a lathe....a renewable.... Today, our youth just replace them.... for new ones....the republican way....What's the matta wit you!
Last edited by Eaglesail; 10-06-2017 at 03:55 PM.
Fast
Todays higher quality rotors come balanced to prevent shake at higher speeds. If they are warped, turning them throws them out of balance. If they aren't warped, then its advisable to have them turned just enough to have a new mating surface applied.Originally Posted by Eaglesail
Posting Permissions
Reply With Quote
Bookmarks