Hi.
How would you check if the rear brakes of a vehicle are contributing a decent/proper amount of stopping power, or they are not performing as they could ?

 

Not sure that I understand stopping power. Do you mean the manufacturer stopping distance spec?

 

Most garages will have a device to do this ... a 5 minute job

Alternatively find a quiet piece of road , slam your breaks on and examine the skid marks , you should be able to trace them back to each tire , the more pronounced the mark , more that tire has braked

 

Late cars will have abs,so cars don't create skid marks. I can only suggest in using the hand brake but gradually.

 

Late cars will have abs,so cars don't create skid marks. I can only suggest in using the hand brake but gradually.

Why do I get the impression this is not a late car ?? ..

From search ...
"It would be inaccurate to say that Anti Lock Brakes (ABS) would not leave any skid marks. They actually do leave skid marks but they are not so prominent that is they are light. In addition to that the marks do not occur as a solid line but as a dotted line which happens due intermittent working of brakes in ABS...."

Would using a hand break tell TS what he wants to know?? Does a handbrake cause breaking in the same manner and by the same mechanism as foot break??
.

 

With or without ABS, take it to a garage/test centre and ask them to do a proper calibrated test.
Lives depend on properly functioning brakes so if there is any suspicion do it properly.

 

Would using a hand break tell TS what he wants to know?? Does a handbrake cause breaking in the same manner and by the same mechanism as foot break??
.

The rears aid the front via a brake proportioning valve,as on my Ford Sierra. I suppose on a hill,will test the rear performance

 

The rears aid the front via a brake proportioning valve,as on my Ford Sierra. I suppose on a hill,will test the rear performance

Specifically, are you asking about the Ford Sierra or another brand/model of car?

Is it disk on all 4 wheels or only front (or no disk)? Front wheel drive? Most important, have you visually inspected the brakes?

 

Usually if the pads are bad you'll hear a screeching metal on metal sound, if you have issues with the master cylinder or leakage of fluid you'll see a drop in fluid levels. If your pedal goes to the floor or seems like you don't have brake power, it might be the booster.

My issues with my truck was it went close to the floor after replacing the booster, but the calipers on the front wheels and the master cylinder were both bad. Old vehicles will do this, depending on the model and make of the car will determine some factors. What is the make and model?

kv

 

...What is the make and model?

2000 Land Rover; 4 discs and ABS. Rear pads not worn at all, rear wheels spin freely with no friction, no wear on discs either. Am afraid they are not providing braking assistance to fronts...
-Just back from a 2500 mile trip-

 

Sounds normal to me. The inertia is thrown forward onto the front axle when braking. Many rear pads last a very long time. The same occurs with drums.

Find a straight downhill stretch and lock up the brakes........do you veer? Do you need steering correction?

Accelerate to high speed in reverse......hard brake(inertia will be thrown on back axle). Veer?

Again and this time lock them up. Veer?

Some brakes self adjust in reverse. So the first few reverse runs might be adjusting.

Download a manual. There is usually a procedure.

 

Sounds normal to me. The inertia is thrown forward onto the front axle when braking. Many rear pads last a very long time. The same occurs with drums.

Same on my Harley... I have to replace front brake pads every 5-10,000 miles, the rear pads last forever. In fact the rear brakes will lock up easier since the weight pitches to the front when stopping (nose dive).

Best way to check on your own would be to jack up the rear and hit the brakes see if it catches. It is possible that air in brake lines could be making the rear fade... in which case you need to bleed them.

70-80% of braking is on the front... depending on how hard they are stopping. If you look around you might notice that front discs are much larger on vehicles for this reason.

 

Sounds normal to me. The inertia is thrown forward onto the front axle when braking. Many rear pads last a very long time. The same occurs with drums.

That might be true for RWD vehicles of that vintage, but more modern Ford's with FWD, ABS, and speed control wear out the rear disk pads first. It is all in how the ABS proportioning valve is set.

I agree with the road tests you suggest, but "high speed" doesn't mean 80 mph. He should be able to tell the difference easily at 20 to 30 mph or less.

 

https://physics.stackexchange.com/questions/309975/car-physics-braking-and-accelerating

It's physics the center of mass shifts... it has nothing to do with rwd... the motor is cut when you are braking... usually... unless you're trying to tokyo drift or something like that... perhaps engine braking with manual trans...

 

https://physics.stackexchange.com/questions/309975/car-physics-braking-and-accelerating

It's physics the center of mass shifts... it has nothing to do with rwd... the motor is cut when you are braking... usually... unless you're trying to tokyo drift or something like that... perhaps engine braking with manual trans...

Tell that to the Ford engineers. Perhaps you should do a thought experiment. What if the front brakes were disconnected? Would they still wear more?

 

So you're saying they want to reduce the use of the front brakes so it stops slower? That works... I would like to know the new science behind stopping faster using only rear brakes... if you have data and study to support it I'm all ears.

If the front brakes were out. you wouldn't stop as fast... you're dragging the rear wheel... it will screech faster... try it on a bicycle.

 

It has nothing to do with "stopping faster" using only the rear brakes. Focus on your assertion that because of the CG shift, the front brakes wear more. That simply is not a given in modern cars.

My point is that thousands of Ford Fusion owners complain about the rear brake pads wearing out. I can go through 3 sets of rear (mostly the inner pad) for a single set of front pads. Ford denies warranty based on it being a "wear" item. And the service rep tells me that is the way it is supposed to be. I think the Ford speed control, which sets not only a minimum, but also a maximum speed, e.g., when going down hill. In the down hill situation, I suspect the rears are applied almost exclusively,

Front or rear can be set to wear 0% to 100% compared to the other. That was my point. Sure, a lot of RWD cars were set to wear the front brakes first, because normal engine braking helps balance the rear. With front wheel drive, the situation is reversed.

 

Same on my Harley... I have to replace front brake pads every 5-10,000 miles, the rear pads last forever. In fact the rear brakes will lock up easier since the weight pitches to the front when stopping (nose dive).

Best way to check on your own would be to jack up the rear and hit the brakes see if it catches. It is possible that air in brake lines could be making the rear fade... in which case you need to bleed them.

70-80% of braking is on the front... depending on how hard they are stopping. If you look around you might notice that front discs are much larger on vehicles for this reason.

OhYa, that was the other thing that was wrong with mine, air in the lines because the calipers were leaking.

kv

 

Air in hydraulic system doesn’t work well. You’ll have to fix that.

Glad I don’t own a fusion. Never been a ford guy.

 

He's right. Both cruise control and ABS control strategy has evolved over the years. I should watch what I say about modern contraptions.

What will be the next break-thru, digital active stabilization perhaps? Sorta like the tanks?