Help! CVT clunking from D to R and steering shakes when high speed braking.

Hi Everyone, I'm new to this forum.

Obviously, I came here to get some information regarding my Mirage 2015 (Hatch, Thai Made). Got 31,000+ kms already with it.

Done so far:
1. Replaced Air Filter (engine) at 20k kms.
2. Change oil every 5k (5w-30).
3. Just recently replaced CVT fluid (J4) at 30k kms at the dealership.

Problems:
1. I observed coming from a 1hr+ drive, a big clunk from the transmission when shifting from D to R (done this at complete stop). Even after I changed the cvt fluid, the problem still exist. However, it bothers me because after it clunked and shift again from D to R, it does not clunk anymore. It's very annoying every time I will shift to R hoping that it will not clunk. What is the solution for this? has anyone here experienced like this also?

2. When driving at 80kph+, steering wheel shakes/vibrates when applying brakes. Could be worn out rotors? but it is possible at 31,000kms rotors from our mirage could be worn out already? what else could have caused this problem?

Hello kulot and welcome to the forum. :)

Sorry I can't be of help regarding your CVT as I have a manual transmission in mine. Hopefully someone here will come along with advice.

Regarding brakes, try rebedding your brakes. It shouldn't cost a thing. :)

Quote:

---

Originally Posted by kulot

...When driving at 80kph+, steering wheel shakes/vibrates when applying brakes.

---

The most likely cause is that your front rotors have a runout or thickness variation problem. Or in more common terms...the rotors are warped. Even a rotor that is off by a few thousandths of an inch can cause brake pedal pulsation or a vibration in the steering wheel when the brakes are applied. Yes...even at 30,000 kms...especially if you are doing a lot a braking in city driving.

The repair in this case would be to re-surface or replace the rotors. My personal preference is to just replace them. In my experience, resurfacing rotors tends to fix the issue temporarily. The pulsation/vibration usually returns.

Quote:

---

Originally Posted by kulot

could be worn out already? what else could have caused this problem?

---

A few members reported brake pads wearing out with excessive brake dust at as little as 15k miles. This is usually a tell tale sign of brakes dragging or not releasing fully / tight seals on the caliper, dry caliper etc and can cause excesse heat in the brakes and warp your rotor. Not saying it's necessary anything to doo with your possibly warped disk but excessive heat or excessively quick cooling (was hot hit a puddle) is what is usually blamed for warped rotors.

If you wanted to check for a dragging caliper its very easy. Go for a long drive and check if your front brakes are equally warm and not excessively so. (assuming they're not both messed up lol it's a judgement call)


Eggman how do you do that

Quote:

---

Originally Posted by Top_Fuel

...especially if you are doing a lot a braking in city driving.

---

yes indeed a lot of city driving. actualy my daily trip is around 70kms. Ok, ill with my local dealer about rotor replacement. I just cant accept the fact that my rotor is already worn out at 31k kms :(

Quote:

---

Originally Posted by MightyMirageMpg

A few members reported brake pads wearing out with excessive brake dust at as little as 15k miles. This is usually a tell tale sign of brakes dragging or not releasing fully / tight seals on the caliper, dry caliper etc and can cause excesse heat in the brakes and warp your rotor. Not saying it's necessary anything to doo with your possibly warped disk but excessive heat or excessively quick cooling (was hot hit a puddle) is what is usually blamed for warped rotors.

If you wanted to check for a dragging caliper its very easy. Go for a long drive and check if your front brakes are equally warm and not excessively so. (assuming they're not both messed up lol it's a judgement call)




Eggman how do you do that

---

Thanks for this information. If I may asked, could it also be frequent going through an uneven surface with small amount of water could affect the caliper seal? or the guide pins?

Nah realistically unless your doing something out of the ordinary the cars equipt to handle whatever you throw at it. In my opinion, "things like this happen" and i wouldn't waste time investigating it further than checking your brakes are not dragging.

Just my 2 cents... Probably not an issue but hate to waste $100 on some rotors you know

Quote:

---

Originally Posted by MightyMirageMpg

Eggman how do you do that

---

Did you try a search for bedding rotors?

:)

I too used to blame warped rotors. I think it was cyclopathic (where are you??) who straightend me out.

After a hard stop, try to roll a bit to allow even cooling along the rotor surface.

Quote:

---

Originally Posted by Eggman

Did you try a search for bedding rotors?

:)

---

No. I thoroughly enjoy the airplane sounds you make while you spoon feed me the information. Lol

I've never heard of this for warped rotors but i guess it makes sense as it works for clutches.



Per google and none of my information below;


Bedding In Brake Rotors

Anytime you install new brake rotors, brake pads, or both, it's advantageous to bed in your new brakes. Bedding in your brakes is just an industry term to explain breaking in your new brakes. Bedding in your brakes helps transfer an even layer of brake pad material onto the brake rotor which assists in smoother brake operation and improved braking power.

Having a uniform layer of pad material on the brake rotor is essential to minimizing brake squeal and vibration. For this procedure, you will need a good stretch of road and no traffic.

Use common sense and take precaution as BrakePerformance does not take responsibility for erratic driving, accidents, or damages done.

Note: When using Brake Performance Zinc-Coated rotors, as soon as you start braking, the friction from the pads will strip the zinc from the pad surface, turning it Silver and leaving the holes, slots, and the rest of the rotor zinc coated in the color you selected.

Perform 3-4 medium stops from 45mph. Slightly more aggressive than normal braking. You don't need to come to a complete stop for each pass. This brings the brake rotors up to temperature so they are not exposed to sudden thermal shock.
Make 8-10 aggressive stops from 60mph down to 15mph. For this set of semi-stops, you want to be firm and aggressive, but not to the point where ABS activates and the wheels lock up. It's important to note that you don't come to a complete stop but rather a semi-stop (~15mph). Accelerate back up to 60mph as soon as you slowed down to your semi-stop.
The brake pads and brake rotors are extremely hot at this point and sitting on one point will imprint the pad material onto the surface unevenly. This can cause vibration and uneven braking.
You may notice that your brakes will start fading, and sometimes smoke, after the 6th or 7th pass. This fade will stabilize and will gradually recess once your brakes have cooled down to normal operating temperatures. Drive carefully as your brakes may feel softer for the next few minutes.
Try not to come to a complete stop and find a stretch of road where you can coast for 5-10 minutes, preferably without using your brakes.
After the break-in procedure, there may be a light blue tint on your brake rotors as well as a gray film deposit. The blue tint shows that your rotor has reached the appropriate temperature during the bedding process, and the gray film is some of the pad transfer material.

Some cars and trucks require two cycles of the bedding in procedure. This may be the case if you are using old brake rotors with new brake pads, or new brake rotors with old pads. This may also be the case if you don't think you fully heated up the brakes in the initial bedding procedure. In any case, it's required that you wait at least 10-15 minutes between each cycle as you don't want them to overlap.

Quote:

---

Originally Posted by MightyMirageMpg

No. I thoroughly enjoy the airplane sounds you make while you spoon feed me the information. Lol

---

Haha! I wanted to add more to it but couldn't at the time.

Thanks for posting that info. More can be found here: Brake warp myth

Now I'm no expert, but it seems to me worth it to at least try rebedding the brakes. Imagine if the rotors are still usable but get replaced anyway. The original problem could very likely return because it is a matter of behavior, not faulty parts.

Any competent shop can check for lateral runout on a rotor with a dial indicator. Here's a video explaining how it works...

https://www.youtube.com/watch?v=IzPn0RnH4cQ

I'm an ASE Master Technician. If my steering wheel shakes in my hand when I hit the brakes, the above test is the first thing I'm doing. Just sayin'... :D

Quote:

---

Originally Posted by Top_Fuel

I'm an ASE Master Technician. If my steering wheel shakes in my hand when I hit the brakes, the above test is the first thing I'm doing. Just sayin'... :D

---

Thanks for posting the video. I'm pretty sure lateral runout is covered in one of the articles in the search results, but this covers it too.

It's nice that you have access to the tools to measure this. Not everyone has a micrometer & runout gauge - I don't.

So if you come across excessive lateral runout, would you turn your rotors or replace them? What do you think about rebedding the rotors?

I just wanted to post that video so you guys would see what a shop should do to check for a runout problem. No shop should just throw new rotors on a car without doing a couple of checks.

Quote:

---

Originally Posted by Eggman

...if you come across excessive lateral runout, would you turn your rotors or replace them?

---

I haven't resurfaced a rotor on any of my personal vehicles for 20+ years. This is for a couple of reasons.

If the rotor developed a thickness variation problem, it may not be a quality rotor to begin with. I've never had a pulsating brake pedal or runout issue with quality rotors. But I have had problems with OEM and cheap aftermarket rotors. Normally you think OEM means quality, but with brake rotors that is not the case for a lot of cars.

If the rotor developed a thickness variation to begin with, it happened for a reason (low quality materials, excessive heat build-up, etc). If you remove material from the rotor to make it smooth again, you also just made it thinner. So now its ability to handle heat has been reduced even further. The likelihood of the problem returning is high.

Rotors aren't expensive and I don't like doing a job more than once. So when my car needs rotors, I just replace them with high quality aftermarket. I've had good luck with rotors from brakeperformance.com. If someone is on a budget and money is tight, go ahead and resurface them.

Quote:

---

What do you think about rebedding the rotors?

---

When you install new rotors/pads, that is a good idea. If you have existing brakes, then trying to re-bed the pads to fix a pulsating brake pedal or shaking steering wheel is not going to fix the problem.

Here is one issue I didn't think about which could be a problem for cars that are parked for a long time...

https://www.youtube.com/watch?v=B_yussnt28A

30k is very premature for warped rotors. It depends on how you use your brakes. I personally wouldn't bother trying to get someone to turn rotors. They are cheap enough to just buy new(aftermarket). Plus you aren't down a vehicle while waiting for someone to turn them.

As far as your clunk goes, does it do it all the time? Only from D to R or R to D as well?