Handling Problem On Hard Braking (2 Door)

[Owl]

Must be a slow day Mr. "Cubed".

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[userdude]

I have noticed the same issue, pulling to the left. Also happened twice (last couple weeks). I assumed it was ABS; I've had other trucks wander left/right on hard breaking. Don't seem to have any steering issues otherwise.

 

[Lcubed]

Must be a slow day Mr. "Cubed".

Just riding out the storm

 

[Owl]

I hadn't considered alignment as an issue... since the Bronco is so new, but that'll definitely have to be put on the list of possibilities.

Overall, I can see a little more brake and straight-line testing is required at this point. I've got to get a better sense for what is going on... when it is occurring.

 

[HBTFD]

I've heard (from an alignment guy I trust) that some manufacturers "set" the alignment by raw measurement of adjustable parts like tie rods, but only truly align a handful of vehicles off the line. I'm not sure if this is true for Ford or the Bronco, but it could be a contributing factor.

Every vehicle is aligned using an alignment machine right after it comes off the chassis line. The measurements are recorded and referenced if a warranty claim comes up. At my old plant the headlights were aligned at the same time.

 

[Durangatan]

Not surprised. Big, heavy vehicle. Tires and wheels that are not engineered for those stresses. What do you expect? Despite peoples’ postings about “handling like a sports car”, the Bronco is a big, heavy beast that is not designed for precise handling.

 

[LowerSlowerDelaware]

Why are you running 37-39 psi?

That‘s seems a little too high for Cali Hot ambient air temps, road surface temps and moderate to long trip distance.

Start at 35 psi and see if you handling improves and if not then proceed to lower your psi until you find your sweet spot.

Don’t trust the TPMS, I seen 2-4# discrepancies airing up/down.

Just my .02

 

[Owl]

I'll try the air pressure change... and go down to 35 and see what that does.

I don't trust TPMS that much. Got my own gauge hooked to my old Craftsman compressor. I've checked that with a couple other gauges... seems to be accurate enough.

 

[BAUS67]

Mr. Sandsux... what model are you driving? I'd think something above a Big Bend or any SAS model would have larger/different brakes than the standard 2DR Base.

I wonder (don't really know) if the software for traction control could be an issue. I remember in someone's Forscan post where you can set the tire size. I assumed this was for correct speedometer, but I wonder if there are any other hooks.

First, as far as I know all trims of Bronco (2DR and 4DR) carry the same brake rotor/brake caliper/brake pad/unit bearing. The Braptor is a different story.


Second, you have brought up a very good question. Makes good sense that the ABS would use tire size in it's control of the braking system. Bigger tires are usually heavier requiring more stopping power/distance. It makes sense. I would give the 30's a try just to see if it still does it.

Generally a "pulling" under braking is caused by caliper slides not lubricated, not allowing caliper to slide when brakes are applied. Or an issue with the caliper itself, piston inside that pushes on the brake pad could be sticking. These are things more associated with older vehicles with higher milage on them, but in today's world you can never tell.

 

[Owl]

And... I don't expect it to handle like a sports car. However, it should stop in a straight line without a lot of fuss. At least that is the hope.

 

[RHeinz]

Curious, did your two “panic stops” require the ABS to actuate?

Have you ever tried an “full on” antilock stop from say 40 or 50 MPH?

 

[Owl]

No... stop wasn't enough to activate ABS.

I have not tried a full-on stop from 40-50.

The real problem seems to be steering control from say 60-70 during the stop.

I will have to go play with this in the next day or two (i.e. go through a few stops), and observe what exactly is going on as best I can.

 

[International_George]

My BD has done similar squirrely stops. I’m wondering if part of the issue is from my reaction (maybe pulling with my right hand). I’ve also never had a vehicle with this large of tires and short wheelbase so I don’t know what to expect for high speed stops.

 

[Owl]

That is why I figured I better get out there on an open road and try a few stops from 60 or 70 and just see how the beast feels, and what my reactions are.

Kind of like when I was a kid in Wisconsin and I'd take the parent's car to a vacant parking lot with snow on it and put it in a few spins/skids just to get the feeling of what it was like.

 

[AMCheese]

I had the same experience when braking hard with my 2dr Black Diamond. The issue seemed to go away when I upgraded to a wider rim. Went from stock BD 7inch wide rim to 8.5inch Method rim, same tires. This made a big difference for me, feels more solid and planted.

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