45 votes
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Why do the brakes "freeze" the suspension?

I made a crude sketch illustrating the relevant points of the shown image. Brakes engaged: The center of gravity is above ground, the brakes "try" to slow down the car, the car itself "...
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  • 7,828
27 votes

Broken Coil Spring - How urgent is the repair?

That spring can rotate and rip out the tire - catastrophic loss when entering a bend could mean driver, occupants, other drivers, and/or bystanders could be singing with the angels... Ground the car ...
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20 votes
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Discovered disconnected part when removing wheels

I agree with @resident_heretic that these are the link arms for your stabilizer bars. The bar acts as a torsion spring that tends to keep the car level during cornering. With the links broken on the ...
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16 votes
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Motorcycle Speed Wobble - How do I figure out the problem?

Motorcycle Speed Wobble Troubleshooting Troubleshooting speed wobbles can entail looking at quite a bit. Here are some bullet points on components you need to check on your bike for integrity and ...
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  • 32.8k
16 votes

Broken Coil Spring - How urgent is the repair?

My biggest concern with issues like this is causing additional damage since the spring is no longer being supported the way it was designed to be. Also, the rear suspension is (obviously) compromised,...
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14 votes

What are the Advantages of a Single Side SwingArm on Motorcycles?

Background While various items such as maintenance and ease of tire removal are cited for the SSSA (Single Sided Swing Arm) design, initial testing and development of all these designs were started on ...
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14 votes
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Spring tensioner safety

I use two part spring compressors like you show here on a regular basis.* I think you'll be fine but there are some good things to watch out for. Watch out for the threads. If the compressing ...
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  • 24.3k
14 votes
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Vibration at speeds between 40-47mph

Hitting a bump at speed can cause several problems: Tire or wheel damage: generally this requires a replacement tire or wheel Suspension damage: a suspension member could have been bent or damaged by ...
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  • 14.5k
13 votes
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Reusing self locking nuts

I'll make a couple of cogent points, but I doubt I'll be able to organize this coherently. Go get and read Carrol Smith's Nuts Bolts Fasteners and Plumbing. This is religious tome-level knowledge ...
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  • 12.2k
13 votes

Discovered disconnected part when removing wheels

Looks like a stabilizer bar link. They come in pairs one on the left and one on the right side. They attach to the stabilizer bar. Stabilizer bars are part of a car's suspension system. They are ...
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  • 3,822
13 votes

Broken Coil Spring - How urgent is the repair?

The basic issue from a mechanical point of view is that the spring (not the shock!) is what supports the weight of that corner of the car. Clearly, with a piece missing, it is not doing that as it was ...
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  • 2,929
11 votes
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How Urgent is it to Replace Worn Out CV Boots

From my experience of CV boots, you need to replace them immediately if you want to keep the CV joint it covers. It doesn't take long for dirt to destroy the joint once it gets inside the boot. If ...
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11 votes
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What are the advantages of upside down forks?

There are several advantages to upside down forks Rigidity Caliper Mounting Stability Reduced Unsprung Weight Reduced Sprung Weight Reduced Stanchion Friction Levels Increased Stanchion to Slider ...
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11 votes

Pros and cons lowering sedan?

For God's sake don't I'm still to see a car that was lowered properly. From what I can remember now you will have these issues: The car will jump at every small irregularity in the asphalt. Wheels ...
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11 votes

Why do race cars need suspension?

Suspensions do two things: they smooth out a bumpy ride, and as such are more of a comfort thing. In fact, production cars have their suspensions tuned at the factory for some kind of compromise ...
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11 votes
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Is alignment needed after replacing upper control arms?

ABSOLUTELY Yes, when you do any major work to the front suspension, you need to have the alignment done. Even though the parts are "basically" the same, they are not exact. Newer parts will be ...
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10 votes

Car pulls to right when letting go of accelerator?

The vehicle in question is a front-wheel drive. FWDs are sensitive to front wheel alignment, since the front suspension and wheel linkages work under different conditions when accelerating and not ...
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  • 1,282
10 votes
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Effects of sway bar stiffness on rough, uneven roads

tl;dr: stiffening one of the sway bars on a car will cause that end to be more likely break loose in response to transients. At a high level, the sway bar acts as a spring just like any other. You ...
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  • 24.3k
10 votes
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Wish to understand why non-stock vehicle alignment is an issue

Factory specs assume factory parts. Each modification you have made changes the angles at which the suspension operates so those angles no longer apply. This is especially true on truck lifts where a ...
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10 votes

Why do the brakes "freeze" the suspension?

As it turns out the answer is very obvious and frankly quite simple. Consider a 1 meter long plank. Now if you lift up the right side of the plank by 10 cm (0.1 meter), the left side moves a bit to ...
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9 votes

Do springs wear out?

Springs do wear out overtime or with severe duty use. You can determine if they are sagging by checking the ride height. Where this measurement is taken and what is normal varies with each vehicle ...
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9 votes
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What makes a worn car shock spongy and soft?

Shocks/struts can either come charged with nitrogen (gas shock) or conventional (without a charge). Both can wear out over time. Shocks should be replaced around 50k miles under normal conditions. ...
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9 votes
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"Always Replace" (torque-to-yield) Bolts

I cannot tell you directly if the bolts you are using are Torque to Yield (TTY or T2Y) bolts, but if Bently says to replace them, you bet I'd do it. What are three bolts in comparison to the well ...
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9 votes
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How did luxury cars provide smoother rides without active suspensions?

Assuming they were the base models, the two cars you mentioned (Acura TL and Mazda6) are both Front-Wheel Drive (FWD), while the Mercedes is Rear-Wheel Drive (RWD). The FWD cars, having both their ...
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  • 6,017
9 votes

How to demonstrate that rear shocks are failing?

There should be no oil visible on the shocks. If you see oil that means they're not damping as they should be because the seals are compromised. They most certainly shouldn't be dripping, regardless ...
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  • 39k
9 votes

When to replace struts?

Those look very worn to me. Of course it's your choice, unless your locality requires vehicle safety inspections, to keep driving on worn suspension parts but it's not the safe choice. The fact that ...
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  • 8,829
8 votes

Why is my car tramlining(pulling/veering when I hit road imperfections)?

What you are describing is called bump steer. This is caused by a toe change when the suspension travels vertically. Common Causes include Incorrect tie rod height or lenght steering rack that is ...
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8 votes

Load on bed of pickup for extended period of time

Your truck is designed to carry that load. If you consider carrying a full set of passengers. 1 in the front, 3 in the back, that weight would exceed your current load of 500 pounds. I would not be ...
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  • 32.8k
8 votes
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Ohlins Rear Motorcycle Shock - How do I setup, care for and tune it?

Overview In terms of rebuilding the shock, there are similarities between models but there are unique differences between them that make it impossible to review all of the nuance. I'll only give a ...
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  • 32.8k
8 votes

Effects of sway bar stiffness on rough, uneven roads

Adding a sway bar will result in a harsher ride I've tried to explain the mechanics with this side-by-side graphic: Explanation When a wheel encounters a ditch, the weight of the vehicle on that ...
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