Does anyone know what is the towing capacity of an 89 Bronco II 4 x 4 witha six cylinder? I am interested in towing a 17 foot fishing boat, and have my eye on a used Bronco II.

Also, the Bronco has a ball already in place, using the existing bumper, but the previous owner did not have an external towing bar installed. Would you recommend having a Reese hitch installed?

 

Ok, your ok if the boat is isn't over 2100lbs, after that it gets really tough to move. Also unless the the boat is under 1000lbs with a 100lb tongue, go for a aftermarket under-bumper hitch. After tearing off my rear bumper at home depot (sand bags) with ~1500lb load, i went to u-haul and they hooked me up.

 

Can't speak to the weight ratings, but you need to be careful about the total rig's behavior.

Bronco II is a relatively high-sitting, narrow-track, short wheelbase vehicle- not the ultimate in stability for towing. Depending on the weight of the trailer (fully rigged glass bass boat, light jon boat w/ small motor, or something in between?) and it's handling characteristics, you might be in for some "fun" while towing. A heavy trailer that handles well is OK, while even a light but ill-behaved trailer may be unsafe.

If the trailer is short-wheelbase (axle-to-coupler), narrow track, and sits the boat high on the trailer, you could get substantial sway from a panic stop, crosswind, wake from a passing semi, or rough road. With the wrong input, some rigs will start dancing and yanking the tow vehicle side-to-side- and maybe cause loss of control.

If you've got a light boat sitting high on a short, narrow, high lightweight trailer, keep the trailer loads light. Coolers, tackle, camping gear, etc. might better go in the tow vehicle.

I've been surprised how minor changes in weight distribution affect how the trailer handles. Generally, you want as much of the trailer weight directly over the axles, rather than in each end of the boat. Tongue weight should generally be 5 to 10% of total you might find a specific loading in that range that works best- and maybe some loadings to avoid.

If you've got a relatively heavy rig, you may want to check out surge brakes- they improve both your stopping and handling margins.

I second the notion to go with a frame-mounted receiver hitch. The one I put on the Chevy S-10 I used to have looked stronger than the bumper-to-frame attachments on my F-350. Plus, they're not bad to bolt on yourself- just make sure to use the hardened bolts that come with the kit.

Once you're set up, I recommend some test-drives on known roads in low traffic conditions. Probably the best test is a hard stop on a bumpy downhill- but make sure you've got a safe runout (no stops, sharp curves, etc). in case you need to get off the brakes. This should tell you if you've got adequate emergency stopping power, and also uncover any tendency to sway. Another sway test is to gently move the steering wheel from side to side a bit on a wide, open highway. If you get the feeling that the sway is increasing or comes on too strong, you've got an issue.

My $0.02. Your results may vary. In this case, they certainly will, since each combination of base tow vehicle, shocks, wear on shocks, trailer, total weight, and weight distribution is probably unique.