Braking Time Car will Jerk forward

[Acertey]

Hi Guys,

 

Recently i just did the following:

Change of all Engine Mounting,

Change of All Suspension;

Gear Box Over haul;

Rotor & Brake Pad Change(Front done, rear using drum which not done);

Brake Oil Change

 

However every time when i brake, there seems to be a jerk which a sound that "thump" with a jerk forward before coming to a full stop. Even before i did the above changes the "thump" before come to a full stop is there. Initially i thought is the engine mounting. Does any brothers here encountered the same problem?

Edited September 12, 2011 by Acertey

[SimonTan]

Did it happen for reverse braking?

 

The sound is from normal gentle braking or only during sharp hard braking or with ABS activated type of emeregench braking?

 

[Acertey]

reverse no sound but also jerk.

 

Normal braking...

[Civic6656]

It could be the gearbox mounting is worn...

[Mecontle]

front suspension not proper calibrate ? if u press front sides of ur bonnet see if it vibrates up & down (bad) or not shaking (good)

[SimonTan]

Something that is loose.

Like some mounting for gearbox or suspension arm.

Or it could even be your car seat that is loose.

 

Hard to say.

 

[Spiderman302]

  On 9/12/2011 at 2:27 AM, Acertey said:

Hi Guys,

 

Recently i just did the following:

Change of all Engine Mounting,

Change of All Suspension;

Gear Box Over haul;

Rotor & Brake Pad Change(Front done, rear using drum which not done);

Brake Oil Change

 

However every time when i brake, there seems to be a jerk which a sound that "thump" with a jerk forward before coming to a full stop. Even before i did the above changes the "thump" before come to a full stop is there. Initially i thought is the engine mounting. Does any brothers here encountered the same problem?

 

 

Is it a Honda City ?

[Acertey]

wah spot on Honda city, 2007.

 

Engine Mounting i just all changed,

Suspension also, shouldn't be these 2 becos before i change this thump is already there.

[Acertey]

anybody can help?

[Asure7]

Not sure if it helps since different cars, although similar symptoms.

 

Many E60s (after about 40-60k) has this problem: Jerk just before stopping.

After all the troubleshooting, change this change that, it's gearbox mechatronics problem. It jerks under "D", but not when it is in "S" (sports) mode. Found that it jerks if the gear shifts to 1st gear just before stopping (using "manual" mode).

Had to change the mechatronics for $4-5k and the problem went away.

But it doesn't really happen when reversing though.

 

Did you change your ATF, and use the original Honda one? (assuming the gearbox overhaul was properly done)

Edited September 13, 2011 by Asure7

[Acertey]

yes i did, in fact i also did a gearbox overhaul.

 

Before the gearbox overhaul this loud thump is already there, but the thing is after gear box over haul the thump is still there, it's weird.

 

Unless the gear the is link to the starter clutch is also damaged

[Watwheels]

Last time I encounter this was on a European car, the thump sound during braking is caused by the programming of the gearbox, downshift of the autobox when slowing down/braking. Feedback to AD, AD feedback to HQ and they follow up with new software couple of weeks later, did a reflash, thumping gone.

[Jim]

  On 9/13/2011 at 2:01 AM, Acertey said:

yes i did, in fact i also did a gearbox overhaul.

 

Before the gearbox overhaul this loud thump is already there, but the thing is after gear box over haul the thump is still there, it's weird.

 

Unless the gear the is link to the starter clutch is also damaged

 

This is a very important question: Which transmission fluid did you use?

 

If this is a CVT Honda City, you *must* use CVTF or HMMF. If it is ATF-Z1, you must change it *immediately*. And if your mechanic use ATF-Z1 for your CVT City, you should change mechanic too.

[Acertey]

i use CVTF.... oil correct...

[Jim]

  On 9/13/2011 at 1:10 PM, Acertey said:

i use CVTF.... oil correct...

 

In that case, I agree it is probably the startup clutch is worn. You can try and re-calibrate the gearbox... I am not exactly sure how it is done, but the general idea is you disconnect the battery so the ECU forgets the old settings and then reconnect back, start the car and shift the gear from P to L and back again twice. I doubt it will fix a worn clutch, but no harm trying.

[Spiderman302]

  On 9/12/2011 at 5:18 AM, Acertey said:

wah spot on Honda city, 2007.

 

Engine Mounting i just all changed,

Suspension also, shouldn't be these 2 becos before i change this thump is already there.

 

I owned a honda city autogear first generation years back. Got the same problem. Everytime reach traffic light.

Gear still engaged but no right foot. There will be a slight "Thong" sound with a slight jerk forward motion at a particular speed.(dont remember what speed). Jist like the car suddenly go free gear.

 

Called Kah motor, they said its inherited character of the gear box. Ask me to ignore.

 

 

[Acertey]

wah like that, this type of response from KM.

 

Cos i just overhaul the CVT gearbox, can say my starter clutch is in good condition with the correct oil.

 

Actually i am curious what does the starter clutch connects to besides the gear box. Cos when my mechanic took it out, i can see some teeth worn off on the starter clutch. I just wondering if that portion is CAM Shaft or Engine Block if is damage?

[Spiderman302]

  On 9/14/2011 at 12:42 AM, Acertey said:

wah like that, this type of response from KM.

 

Cos i just overhaul the CVT gearbox, can say my starter clutch is in good condition with the correct oil.

 

Actually i am curious what does the starter clutch connects to besides the gear box. Cos when my mechanic took it out, i can see some teeth worn off on the starter clutch. I just wondering if that portion is CAM Shaft or Engine Block if is damage?

 

 

Too bad you cant go back to KM as your warranty is over.

I am no expert in this area. My apology I cant answer your questions.