Touchy Brake Syndrome

[madbomber08]

Have never seen anyone post about 'touchy' brakes on their 4runner. Now i know most people complain of squishy or airy brakes but my problem is a bit different. I came from driving a 1998 toyota camry which was a great smooth driver and the brake feel of the thing is much better than my 4runner. I see no reason, even being an suv, why the 4runner can't have the same overall brake feel as a camry.

I'm used to a nice linear feel on the brakes. You push the break pedal in 1/4" you stop slowly. You put all weight on the brake pedal the rear end comes up off the ground. Well, with my 4runner, it's not a linear feeling. For example, if I push the brake pedal in say 1", the brake will grab enough to send loose objects in the cab slightly forward. In the morning when I go down the steep driveway and have to stop for traffic, oftentimes I accidently lock up the front brakes and skid a ways. It's almost like have to push the brake pedal in a little bit, then let up slightly, then down a little bit farther to come to a complete stop.

Call me an idiot but I can tell it doesnt feel normal. It has 180k on the clock, and as far as I know it has stock suspension components as well, sans the rear coils. There's a considerate amount of nosedive when you really get on the brakes. When it had the Stiff Pedal Syndrome this winter on mornings of sub 0 degrees temps, I had the system flushed with new fluid, but did not have the booster check valve replaced. I am ordering a new one come tuesday.

It almost makes my manny tranny 4runner less fun to drive knowing I always have to think about slowing to stop. If anyone can relate halfway to what I'm talking about let me know. I've never seen anything on this issue anywhere on the forums so I'm not holding my breath.

 

[BrianSD_42]

and as far as I know it has stock suspension components as well, sans the rear coils. There's a considerate amount of nosedive when you really get on the brakes.

Maybe this ....


I don't know, i have a 2001 Camry as my daily driver and the brakes are pretty good. My 4Runner stops pretty quick but it isn't as "tight" and probably never will be. If your suspensions is old (F+R coils, F struts and R shocks) then that will account for a lot of it. Also getting the front brakes checked out or switching to the Tundra mod or bigger pads.

Ohh and see this: http://www.toyota-4runner.org/3rd-gen-t4rs/96830-some-slop-when-coming-stop.html

 

[LittleCaesar]

+1 on the brake booster check valve. The grommet takes about 5 minutes to replace as well. Also check to see if the line running to the manifold is OK.

No SUV or truck will have the same braking feeling IMHO as a car due to their height and weight(mass) distribution but you may want to look into new pads and rotors for a possible fix.

 

[NOT ME OR SOMEBODY]

Mine did this when I first got it 3 years ago.

The brakes seemed to be very touchy while driving slow like in parking lots ect. and not so much when driving faster but still they were touchy.

The rotors were warped or uneven or whatever you want to call it, and this was not so noticable at first but got worse and worse over the next year and a half.

I started to get a bad pulsing, shaking everytime I braked.

I eventually changed the front rotors and brake pads and it smoothed out and still feels normal now a year later.

If you do change the brakes don't go with the cheap stuff, you might regret it ! !

 

[1985taylor1925]

Could be as simple as the pads too. Some pads grip significantly more than others

 

[madbomber08]

Thanks for the responses guys.

As far as taking off the booster check valve, it was really easy. All I did was blow some canned air through it to see if that would clean it out. Although, I could never feel air coming from the opposite side when blowing through one side. Should I try to dump some seafoam in there then let it sit out in the sun for a while? The vacuum tube looked okay. The ends of each side had some cracks but I didn't see any visible cracks on the outside of the tube. Blowing through it yielded that it didn't have any blockage.

I have never checked the pads, and to be honest I don't know how. However, the rotors are smooth all the way across when i rub my finger across them. And my 4runner doesn't really shake when coming from high speed stop which makes me think that the rotors are fine.

There is one more slight issue though. When driving very slowly and braking to a stop, i can feel a slight shudder. It almost feels like the pads are gripping and releasing the rotors really fast. It's not all that obvious but I certainly notice it.

 

[NOT ME OR SOMEBODY]

" There is one more slight issue though. When driving very slowly and braking to a stop, i can feel a slight shudder. It almost feels like the pads are gripping and releasing the rotors really fast. It's not all that obvious but I certainly notice it. "

Classic indication the rotors are warped, ("not the same thickness all around ) you can't feel or see the uneveness in it, it is measured in 1/1000 ths of inches with calipers or micrometers.

Mine did this and it got worse over the months, it was safe to drive on my truck so I waited for good weather and swapped the pads and rotors.

 

[madbomber08]

" There is one more slight issue though. When driving very slowly and braking to a stop, i can feel a slight shudder. It almost feels like the pads are gripping and releasing the rotors really fast. It's not all that obvious but I certainly notice it. "

Classic indication the rotors are warped, ("not the same thickness all around ) you can't feel or see the uneveness in it, it is measured in 1/1000 ths of inches with calipers or micrometers.

Mine did this and it got worse over the months, it was safe to drive on my truck so I waited for good weather and swapped the pads and rotors.

It's weird though. I don't feel it when i really get on the brakes just when I'm coming to a stop very slowly. For example, pulling into the driveway to park it. My parents have a dodge grand caravan that hadn't had brake work done for nearly 90,000 miles and you could REALLY feel and the warped rotors on that thing. In town, on the highway, everywhere you could feel the warpage. I suppose I could just have a much less severe case of it....

How much did machining your rotors cost or did you get new rotors altogether?

 

[JohnsD90]

I paid $80 (set of 2) for new rotors from advance with lifetime warrenty, they were wagners, to get rotors turned it's about $15 each.

 

[madbomber08]

Would it be worth turning the rotors and checking out the pads or should I just go with the tundra upgrade right off the bat?

 

[Tomsriv]

I had that problem when I first bought mine. It was the rear drum brakes. I had them turned even though they were within spec. That along with new shoes and springs (hardware) fixed the problem. I also put in cross drilled rotors in the front with good pads.

 

[madbomber08]

Just replaced the booster check valve. It may feel like it helped a little but I think it's the placebo effect. I did recently replace both rear axle seals so I'll see if there's any residual oil on the pads and rotors and try to clean them really good.

There is another thing I noticed when pushing the brake pedal in. This may be normal and something is telling me it is but I can hear a quick "Psssshhh" of air. Although if something is letting air escape I know thats not good. But maybe it has something to do with the vacuum in the booster?

 

[madbomber08]

Lubed the driveshafts, and cleaned the rear drums and shoes. But something is still getting "caught" for a split second. The touchy brakes are still no where near fixed. But I'm finally starting to feel the slop that I have in the rear. I guess my next objective is to turn the drum rotors and get some new pads.....

If anyone thinks of anything else I can try without spending too much money lay it on me.

 

[liv2bike]

I will agree with you. My runner does the same thing. Brakes are very touchy, especially when I am going slow. For example, when I pull out of the garage and move it, if I just barely tap the brake pedal and am not wearing my seat belt, it will lurch me forward. None of my other vehicles brakes have behaved this way. I am planning to do rotors and pads soon and hope that will help. I want to do the Tundra brake upgrade, but just can't swing it right now. I just replaced all 4 coil springs, put in Bilstein HDs on all 4 corners and Nitto Terra Grapplers. All of this helped but she still does it, especially at slow speeds.

 

[madbomber08]

I will agree with you. My runner does the same thing. Brakes are very touchy, especially when I am going slow. For example, when I pull out of the garage and move it, if I just barely tap the brake pedal and am not wearing my seat belt, it will lurch me forward. None of my other vehicles brakes have behaved this way. I am planning to do rotors and pads soon and hope that will help. I want to do the Tundra brake upgrade, but just can't swing it right now. I just replaced all 4 coil springs, put in Bilstein HDs on all 4 corners and Nitto Terra Grapplers. All of this helped but she still does it, especially at slow speeds.

Mine is the EXACT same way. It's very bothersome as we own a dodge pickup, a dodge grand caravan, and two 4th gen camrys, and i'll be damned if they have the overall same brake feel but my 4runner is just grabby and all too touchy. I don't like it at all.

 

[chitown40]

Check and see if you have a LSPV on your truck. The rumor has it that if you do not have ABS then you have an LSPV, or Load Sensing Proportioning Valve.

My theory is this: Your LSPV is not working correctly. Whenever you modify suspension components (ex. lift the truck) you need to adjust the LSPV appropriately. The LSPV is attached to the body/frame on one end and the rear axle on the other. In your case, you have a stock truck, but over time the springs probably are soft and the excess body pitch might be applying too much front or rear brake. (I'd have to look up in the FSM to tell you exactly how to adjust it, but I believe my travel in the LSPV adds more rear brakes and less fronts.)

Check and see if you have one and then we can go from there to keep diagnosing the issue.

 

[madbomber08]

I'm almost positive I have ABS. When I start the truck I can see the ABS light on the dash light up for a split second.

 

[chitown40]

When you cleaned the drums and shoes, did you adjust them properly?

 

[madbomber08]

I thought the rear brakes automatically adjusted?

 

[madbomber08]

Well I manually adjusted the brakes just a while ago and took a little jaunt around town. At first the e brake was around about 7 to 9 clicks and I could tell it right away because normally its about 5 or 6 clicks. So it seems just a tad bit better as far as pedal travel and touchiness but theres still a slight split second delay/stick (somewhere, front or rear) when I'm coming to a slow stop. If someone wants to see a picture of the rear drums and pads I can certainly put a picture on here because I really believe they don't need to be replaced. I guess it's on to the front end....