Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

Is it Dangerous to drive with bad rear brakes?

Two months ago, my mechanic told me that my back brakes need to be replaced this fall. Last week I began feeling a dragging/rumbling while slowing down and not pressing on the brakes. Just coasting. I had my front brakes replaced 2 months ago. I think the back brakes need to be replaced now and not wait for fall. I plan to take the Jeep in within the next few weeks. My question is: In the meantime, is it dangerous to drive with the back brakes in this condition?



A few more details from the last mechanic visit: The back struts/shocks have seized up. I don't remember which he said. I need a new muffler. It is a Jeep Liberty 2002 and has approximately 150,000 miles on it. The back brakes have never been replaced. I'm going for 200,000, do you think that's a bad idea?

Comments

  • edited June 2010
    If it weren't dangerous to drive with non-functional rear brakes, manufacturers wouldn't go to all the expense of putting them on the car.

    Fix your brakes. Fix your shocks. Your car is dangerous until you do.

  • edited June 2010
    Yes, I think driving with bad rear brakes is dangerous and a bad idea. It sounds like you're metal to metal on the rears.

    Think of it this way. 100% of the inertia of the vehicle is stopped by the brakes. 100% of it is converted to heat energy, almost all of that by teh brakes. At 70 mph that's a lotta inertia.

    In a proper functioning system, it's done in a balanced way, with about 70-80% of the energy being dissipated by the front brakes and sufficient load on the rear tires to keep the rears under control and the car going straight. If you have no pads on the rears, 100% of the energy has to be borne by the fronts, and there's insufficient friction on the rear brakes to be allowing the rear tires to be grabbing the pavement to ensure proper control. Your front brakes and your front tires will be doing more than their share of the work.

    You may get away with it. But if you have to make a hard braking evasive maneuver you're screwed. It could cost you your life.
  • edited June 2010
    Thank you very much "the same mountainbike"! I was hoping to save up the $ in a few weeks but your explanation validates my own thinking. It goes in tomorrow.
  • edited June 2010
    Sincere best. The accidents that never happen are the best kind.
  • edited June 2010
    Simply, if you need to stop the car in a hurry while it is raining, snowing or icy, without rear brakes the front wheels will lock up and you will lose control of steering as long as you have your foot on the brake. The car will slide into whatever you are braking to avoid, without really slowing down much.
    The rear brakes don't do a lot of the stopping, but they are necessary to prevent weight transfer to the front of the car during hard braking. Think of them as an anchor for the rear-end of your car while you are braking. Even if you have ABS, the car is still dangerous on slick roads because ABS increases stopping distance while they are active as compared to hard braking on dry pavement, although they do allow the driver to retain some control of steering.
    You can get away with it for a few weeks, since it's summer, but I would be very careful driving when it's raining. Especially in neighborhoods. Do less than the limit, pay attention and don't tailgate anyone.

    The rear brakes, assuming you have disc brakes, can be very inexpensive to get up to speed. Disc brake pads are cheap and very easy to replace. But often they are not cheap to replace at a garage. Many garages take the angle that the rotors need to be replaced because they cannot legally be cut or turned (same thing), because the factory rotors were too thin. Also, garages will tell you that you need new calipers. This is how two brakes become a $1000 - $1500 job. It is almost never necessary to resurface rear rotors, as they don't often warp, and even if they are scored they will do the job with a new set of brake pads. And calipers do go bad, but not often.

    The muffler should run you under $200 installed. As far as the rear suspension goes, shocks are inexpensive and easy to replace. I would guess you have rear shocks. I think if you are not completely relying on a garage to do this work, and are at all mechanically inclined, you can do at least the rear brakes yourself. If you have rear shocks (not struts, you don't want any part of doing them), you can certainly do that yourself as well. The muffler might be more trouble than it's worth. The more you can do yourself the better.
  • edited June 2010
    Excellent info Kizwiki! I'm a right lane driver who stays within 5 miles of the speed limit. I keep my distance, especially with the brake concerns. I have no qualms with people passing me...I'm following the law and trying to stay safe. With that in mind, I'll be taking my car in tomorrow. I am not mechanically inclined in the least. Safer for me, and everyone else, to take it to a professional. I found a mechanic from this website and he did a great job last time I was there. His pricing was extremely reasonable, AND he listened to me and answered all my questions! I was dumbfounded! He even showed me the bad parts and explained how they work. I walked away learning something and felt more confident with the $ I spent. I suppose I should put this part in his review huh!

    Thank you very much for the pricing ballparks, that will help me with knowing if I am getting a good quote.

    One question remains in my head. The mechanic told me that the rear shocks were seized up but could wait to be replaced in the fall with the muffler and the brakes. I since thought that the rear shocks would be part of the stabilization control of the car. Is that right? I would think that everything works together for best control of your car. I commute 2 hours a day to work, on a high traffic 65 mph highway. I told him this. Sometimes it is very defensive driving.
  • edited July 2010
    Is it Dangerous to drive with bad rear brakes?

    Nah, man/?. Perfectly safe. I do it all the time. (just kidding).


    The rest of the posts are taking care of your issue, but I have to ask, how is this thing driven?

    Rear brakes are hardly used in most passenger car service. Even pickups, the way most people truly use them (they don't tow or haul anything of merit), the rear brakes a hardly wear at all.

    My wife's 1999 Wrangler and my 2002 Wrangler have the OEM rear brakes (drums on rear) with 180k and 90k respectively. The front pads have been service multiple times on both.

    Even my 92 Caravan (dearly departed due to theft) took 14 years to require rear brakes (load sensitive proportioning valve).

    Given 8-9 years and 150k miles, this unit must have seen very little braking. That's between 17k and 19k a year.

    Who has been using both feet while driving?
  • edited July 2010
    Your understanding of the importance of good rear shocks is correct. Frozen rear shocks will not allow the tires to stay in contact with the pavement as well not only over bumps but also going around corners. On corners a car with frozen shocks will unload the inner tire and put additional load on the outer tire, adversely affecting handling.
This discussion has been closed.