Backing down launch ramp with surge disc brakes

[thumpar]

Then why do you think putting a 4WD going down a hill makes your braking better?

Because is locks everything together. This is in the snow and ice that I am talking about too not just normal driving. It does make a difference, at least in my Yukon.

 

[bruceb58]

Because is locks everything together. This is in the snow and ice that I am talking about too not just normal driving. It does make a difference, at least in my Yukon.

It also wipes out the ABS working properly so you stop slower.

 

[thumpar]

It also wipes out the ABS working properly so you stop slower.

My ABS still works in 4wd. They have independent sensors.

 

[Fed]

Without a better description of what's happening I'd guess you're probably locking the front wheels and holding the same brake peddle pressure or is as only natural letting off a little pedal pressure to stop the front locking.
You need to push harder to get more braking from the rear wheels.
Think, front/rear braking capacity, weight transfer & tow ball weight...

Push harder on the brake pedal until all the truck wheels stop turning.

Let me rephrase...
Push harder on the brake pedal until the truck stops moving.

You might want to check the actual weight on the tow ball, it could be a bit too much.

 

[bruceb58]

My ABS still works in 4wd. They have independent sensors.

As long as you aren't going downhill and compression is slowing you down. If the compression from the engine causes a wheel to slip, ABS won't work on that wheel. That is why, in snow, you are way better not ever being in a low gear going down a hill with 4WD or you switch out of 4WD.

Bottom line, being in 4WD does nothing to help you slow down.

 

[thumpar]

As long as you aren't going downhill and compression is slowing you down. If the compression from the engine causes a wheel to slip, ABS won't work on that wheel. That is why, in snow, you are way better not ever being in a low gear going down a hill with 4WD or you switch out of 4WD.

Bottom line, being in 4WD does nothing to help you slow down.

It does when it is slick. Like I said before I am not using compression, just the brakes.

 

[bruceb58]

It does when it is slick. Like I said before I am not using compression, just the brakes.

If you are just using the brakes, it makes no difference if you are in 2WD or 4WD. You could be in freaking neutral! The number of DRIVEN wheels has absolutely NOTHING to do with braking.

 

[thumpar]

Try it in snow and ice in a Yukon.

 

[GA_Boater]

Guys - Unless this topic is about backing down a snowy, ice covered ramp, we have gone far afield.

To the OP, whether you are in FWD or not and the truck is sliding, something isn't quite right. One thing that may help is to put the parking brake on so there is some drag on the rear wheels. It does help because normal bake bias is toward the front brakes and braking in reverse still applies the front brakes harder. It won't hurt to try the parking brake.

 

[bruceb58]

Guys - Unless this topic is about backing down a snowy, ice covered ramp, we have gone far afield.

Went to his claim that putting a vehicle in 4WD backing down a ramp helps which it will do absolutely nothing.

 

[Lou C]

I agree something is not right with the tow vehicle brakes. I towed my F/W H200 that probably weighs the same as the OPs boat with both of our Jeeps and it never felt like it could pull either one down the ramp; even the '98 which is about the same weight as the boat and has small 11" disc brakes.
Does tbe Bronco have rear drum brakes; are you sure that they are working? It's not unusual for the self adjusting function on drum brakes to not function on older vehicles . We had this happen on an '88 Toyota Camry and it became obvious because it was going through front brake pads much faster than normal.

 

[GA_Boater]

Went to his claim that putting a vehicle in 4WD backing down a ramp helps which it will do absolutely nothing.

We are far past that!

 

[thumpar]

I agree something is not right with the tow vehicle brakes. I towed my F/W H200 that probably weighs the same as the OPs boat with both of our Jeeps and it never felt like it could pull either one down the ramp; even the '98 which is about the same weight as the boat and has small 11" disc brakes.
Does tbe Bronco have rear drum brakes; are you sure that they are working? It's not unusual for the self adjusting function on drum brakes to not function on older vehicles . We had this happen on an '88 Toyota Camry and it became obvious because it was going through front brake pads much faster than normal.

That was kind of what I was thinking. Either the front or rear brakes are not working as they should.

 

[Silvertip]

We are far past that!

Shucks -- I wanted to weigh in with my Yukon as I back down snotty ramps and deal with MN snow and ice!! But I would use fiziks (oh yeah -- it's physics)

 

[GA_Boater]

Snotty ramps are OK. Snow and ice - Not so much. Stay with physics, not physic*.



* Might need to look that up.

 

[WIMUSKY]

What if you put the gear shift in neutral so your brakes aren't fighting the motor too? That's only if you know your brakes are working properly. But as mentioned, something isn't right with your tow vehicle. You're not running mudders for tires?

 

[rallyart]

He has a Bronco. It does not have ABS.

Putting the truck in neutral is important. Backing downhill the front wheels will lock first as they have the most brake power. The rears are very unlikely to lock, especially if he has drum brakes on the back of his Bronco. Not need to have power pulling you down while you try to go slower. Neutral is best.

Putting it in 4WD means the front and rear axles turn the same speed. A front wheel locking immediately slows the rear axle. His truck is far less likely to lock its wheels in 4WD than when in 2WD. All four wheels can use the power of the front brakes and that is why he notices that he has no problem with it in 4WD. Empirical evidence of this being effective is in the OP's comments.

No brakes on the trailer going backwards down with surge brakes. You'd need electric over hydraulic to get any braking and that's a big changeover for a small problem.

 

[bruceb58]

The OP states that we gets dragged down the ramp. Only 2 things can be occurring. Either all 4 of his tires are skidding which 4WD won't help or 4WD helps because he has one or more brakes that aren't working properly. Could be as simple as a bad proportioning valve between the front/back brakes.

 

[WIMUSKY]

It would be nice if the OP would make a comment to all the ?s and advice so members can gather more info to make an accurate assessment. As far as we know, the ramp is like ice, extremely steep and he's running very wide heavy lugged tires.... He did say he has "good size tire"......

 

[NYBo]

It also wipes out the ABS working properly so you stop slower.

That is not necessarily true. A study by Car & Driver a number of years ago showed that locked wheels stop a tiny bit sooner than those at the threshold of lock-up. You just can't control where you are going. I supposed this might not hold with some tires, though.