I'm new to the whole trailering thing, so please be gentle.

I've got a 1991 Magnum (www.magnumtrailers.com) trailer under my 1996 Powerquest 290. The trailer is steel, dual axle. Believe it has brakes on both axles (not looking at it right now and the ol' memory isn't what it once was...).

I'm 90% sure the brakes are surge brakes, not electric. There is a master cylinder on the trailer, and the tongue of the trailer is made to slide a bit - there is a shock absorber mounted in the tongue - I'm assuming this is what activates the brakes.

First question - after I come to complete stop, and then start to go forward, the trailer makes a serious *THUNK* as the tongue extends to its limit and the trailer actually begins to move. Pretty unnerving, to say the least. Is this normal, and if not, what should I do to correct it?

Second question - how difficult would it be to replace the surge set up with electric over hydraulic? My new 2005 F-250 has the built in trailer brake controller, might as well use it...

Third, the brakes might have some air in the lines. The master cylinder was replaced last year, and when the former owner tried to bleed the brakes he found the fittings on the brakes themselves are stuck in place. Should I just take it to reliable trailer shop in town and have them look at it?

Thanks!

Mike, your assumption sounds right!

Mike, yeah that is normal. When you mash the brakes, the momentum of the trailer slides and activates the surge brakes. Does not hurt to once in awhile try that to make sure your surge brakes work. Nothing worse than making a panic stop and finding out the trailer brakes don't work

The more electrical you have dipping in the water the more trouble your asking for which is the reason most trailers have surge brakes. I don't mind the surge. I have electric on my toy trailer and they certainly work much better but then again I am not dipping them into the water constantly.

Bleeding brakes on a surge set up probable needs to be done with some type of machine that activates the fluid movement ... I guess I would take it in to make sure it is done right.

Your truck should pull that beast without breaking a sweat. Makes a huge difference in the tow vehicle as you probably found out right away. Make sure you always leave plenty of space in front of you when towing, make sure the lights work, safety chains, and straps on the boat to trailer are in tact and tight. Happy towing.

Thanks Jeff - biggest thing I've towed prior to this was a dinky two-place, one axle open sled trailer. It didn't even have brakes!

I was more worried about the clunking than anything else. The trailer is actually in pretty good shape for being almost 15 years old. Couple spots of rust on the fenders, but other than that it looks good. I haven't towed with the new truck, but the wife's Durango pulled the 290 back to our place from Lansing, about 90 miles, with no problem. Tracked straight and true, no wiggles or sway.

I just want to make sure all is well before we haul the boat over to Grand Haven for Smoke on the Water in July.

DR, if the thunk you hear is metal to metal then the actuator is probably missing a hard rubber stop that should be in there, I can feel a slight tug on mine but I can't hear it.

Electric/Hydraulic brakes are a nicer set-up, IMO, and it's easy to switch them over, the hyd. line that goes to your current actuator should screw right into the electric/hyd unit then all you have to do is put a new coupler on the trailer where the old actuator was. The electric/hyd units are around $500-$600.

For bleeding the brakes any automotive store will have a little vacuum bleeder that attaches to the bleeder screw and draws the fluid through the lines and their cheap around 15-20 bucks they work pretty good but you'll have to loosen the screw which needs to be done anyway, if there's air in there the brakes won't work worth a $hit which could be a problem.

I think the bleeders on the brakes are frozen; that's what the guy I bought the boat from told me and he's been pretty straight up on the whole deal. There's a trailer shop by my house, I'm thinking I'll take it by there and have them take a look at it.

The trailer shop guy (TSG) told me that *if* they couldn't get the bleeders unstuck, it would be $40/wheel for new wheel cylinders, plus installation at $55 / hr. Does that sound reasonable? Or is this something a shadetree mechanic could do? I'll admit to being a little nervous, since this is brakes we're talking about...

My guess is that your clunking sound that you are getting when you take off again, can be helped by bleeding your system. If you have air in the system, which it sounds like you think you might, you will get that sound. Some sound is normal, cuz when you take off again you are pulling the tongue back out to its stop again, but alot of clunking means that piston in the master cylinder is traveling a whole lot, and usually is caused by alot of air in the system. Another cause, if the brakes are older, can be the piston and bore having water in them, which causes some corrosion. This prevents the piston from coming back out all the way on its own,( there is a spring inside the bore which pushes it back out),, to get ready for the next braking.Even though your tongue is coming out when you take off, the piston isn't. The master cylinder never has a chance to pump back up, and you will get lots of clunking. They make rebuild kits pretty cheap, if that is the case.

I think it's exactly like Rich described. Guess I'll take it in to this shop and they can at least tell me what it's going to cost...

It really shouldn't be that hard to get the bleeder unstuck but it's hard to say without seeing it, you can buy a whole new caliper for $150 and the cylinder should be integrated into the caliper, I don't know what he's replacing for $40, can you take a digital photo? $55/hr probably isn't a terrible shop rate though

http://shop.easternmarine.com/index....categoryID=155

Oops, after thinking more (could be dangerous) they could be hydraulic drum brakes then you could replace the master cyl.

Electric over hydraulic is a much better system. No part of the "electric" goes in the water. The hydraulic part is controlled by an electric pump on the tongue of the trailer actuated by a brake controller in the cab of the vehicle.

Surge is OK if they are working properly, but they suck on wet roads ... you have to stop the forward momentum of the truck to engage the trailer brakes. I can't tell you how many times I have slid into the middle of an intersection on wet roads with my old surge brakes and a 311 when the light changed on me.

I think bleeding the system and adjusting the brake shoes correctly will significantly reduce your clunking.

Do you have somewhere you can leave the boat in water overnight? It is MUCH EASIER to work on the brakes without having to slide around on your back underneath the boat. You might be able to get the bleeders loose with a big pair of vice grips after several applications of penetrant like PB Blaster. I would just get all new bleeder valves and replace them. It is easiest to get someone with a power bleeder to do the bleed for you.