Car bounces right before stopping

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ToFI
Posts: 136
Joined: Thu Jun 16, 2011 1:22 am

Car bounces right before stopping

Post by ToFI »

Hi Guys,
I noticed recently that my car bounces a little bit right before stopping at a traffic light. It doesn't matter how smooth or how slow I reach the stop. Just milliseconds before the car fully stops, it'll bounce back and forth a little bit. What can cause this? I think this movement irritates some people.

Chris
Posts: 674
Joined: Thu Jul 22, 2010 2:44 pm

Re: Car bounces right before stopping

Post by Chris »

Could be that the right front strut is wearing earlier than the left one. When you brake, the front of the car naturally dips. If the suspension is uneven between the left and right side, it won't dip and bounce back evenly. You might also notice that, when parked, the gap between the top of the tire and bottom of the wheel well differs between the left and right.

sid3
Posts: 32
Joined: Sat Jan 25, 2020 1:40 pm

Re: Car bounces right before stopping

Post by sid3 »

My guess bad disc brakes. I had the same issue, but it came with other symptoms of bad brakes.

ToFI
Posts: 136
Joined: Thu Jun 16, 2011 1:22 am

Re: Car bounces right before stopping

Post by ToFI »

@Sid3,


Yeah, it kinda feels like from the surface between the brake pad and the brake disc. It's like it tries to bite firm but let loose a little in the end. The brake pads are not worn. I'll try to change the front brake pads to see that'll make a difference. If not, I guess I'll just leave it because I don't have other issues.

Gilberto de Piento
Posts: 1563
Joined: Tue Nov 12, 2013 10:23 pm

Re: Car bounces right before stopping

Post by Gilberto de Piento »

Might need the rotor resurfaced or replaced along with the new pads. Bad rotors will cause vibration when using the brakes. I've had that happen even though the rotors and pads weren't worn out, I think due to using very cheap rotors and pads. They get high and low spots or something. Also make sure the calipers are floating freely.

How old is the suspension? If not the brakes it could be struts as was mentioned or maybe other components have a lot of play from wear.

sid3
Posts: 32
Joined: Sat Jan 25, 2020 1:40 pm

Re: Car bounces right before stopping

Post by sid3 »

When I had this issue I also had to get the rotors turned, $15 at the parts store. Static and kinetic friction had to fight it out. You already know I bought the cheapest pads, but my vehicle has low tolerances.

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Sclass
Posts: 2091
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Car bounces right before stopping

Post by Sclass »

Replace your shocks/struts.

Alphaville
Posts: 2414
Joined: Thu Oct 03, 2019 10:50 am
Location: Quarantined

Re: Car bounces right before stopping

Post by Alphaville »

I came here to say shocks. Check if there’s a leak.

eta: Image



Also, since I’m now just repeating what already’s been said, check the wear on your tires. Bad shocks will cause uneven wear because of intermittent contact with the road, and you’ll end up needing new tires. Ask me how I learned this... :( $$$

ToFI
Posts: 136
Joined: Thu Jun 16, 2011 1:22 am

Re: Car bounces right before stopping

Post by ToFI »

@Gilberto de Piento

The car is 8 years old but with 125k miles. i bought it last year as used.

Gilberto de Piento
Posts: 1563
Joined: Tue Nov 12, 2013 10:23 pm

Re: Car bounces right before stopping

Post by Gilberto de Piento »

If you want to spend the bare minimum I'd probably try turning the rotors first, assuming there is plenty of rotor material left and the pads are good, to see if that fixes it. Or replace the pads and rotors if you want to invest more.

Does the car have struts or shocks (unlikely) in the front? Shocks are easier and cheaper to replace. Are you going to DIY this or hire a mechanic?

At 125,000 miles if nothing has been replaced I would guess much of the suspension is worn out or close. Consider getting an estimate from a mechanic to learn more.

sid3
Posts: 32
Joined: Sat Jan 25, 2020 1:40 pm

Re: Car bounces right before stopping

Post by sid3 »

One way to check a rotor is to run a fingernail across it, if excessively bumpy then replace.
When a brake pad goes bad you will hear a warning squeal when the brakes are applied, from a piece of metal that contacts the rotor when the pad wears too thin.
One way to check a shock is to compress it, if it does not go back to deformed state or does so very slowly, then replace.

Alphaville
Posts: 2414
Joined: Thu Oct 03, 2019 10:50 am
Location: Quarantined

Re: Car bounces right before stopping

Post by Alphaville »

re: inspections

the best bang of the buck i found is to take your vehicle to a chain mechanic (e.g. midas or firestone or pepboys or whatever) and ask for a full inspection. should be under $100. they go through all the major systems. in some places they also check emissions—might be a bit more with that.

they’ll do the inspection and give you a printout with estimates for thousands and thousands of dollars in repairs. if something gets your attention, you ask them to show you (e.g. the leaking shock, or the bent tie rod end, etc.)

then you tell them that you will come back another day. which means: next year, for another inspection.

then you buy your parts online for much less, and take them to your indie mechanic, or wrench yourself.

in this way i avoided many expensive surprises over the years and actually drove a really nice and reliable old truck. was in better shape when i sold it than when i bought it.

aptruncata
Posts: 53
Joined: Thu Jun 14, 2012 11:14 pm

Re: Car bounces right before stopping

Post by aptruncata »

year make model and miles may help.

if it thumps before a stop (like a abs trigger) regardless of how fast or slow before coming to a complete stop; it is likely your ecu.

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