| Author | Message | ||
| Sojourner (Jjimage)
Rating: |
Caution towing with trailer brake; It should be applied same as towing vehicle’s brake. Need to be applying off & on to avoid steady drag to create above designed temperature. Another word driving downhill without pulse braking is automatic transfer the SAME reaction (no braking) to trailer surge-hydraulic brakes with proper setup. However using Jake or retard-er is a CONTENT drag to trailer surge-hydraulic system = HOT brakes. Another word DO NOT uses engine braking or retard-er unless you can turn it off & no in a moment. If trailer free-roll faster then coach’s free-roll, then install a compensator spring to surge unit to keep it from activating until vehicle’s brake applied. As my per previous post (12th post under “RV/Bus plummets 75 feet off Icefields Parkway”) regard to lbs force in static (stand-still) condition. The traveling downhill force is base on relationship which rolls the easiest. Usually trailer is trying to get ahead of vehicle. Base on wind resistant (vehicle break most of it air stream), tires, bearings and so on, so force is less then static force. I would think (without actual testing) 20 to 50% less then static force to determine the spring size. Static force is trailer GTW x grade’s percent = lbs of force. Now it is more complex to have the right size spring for each difference downhill’s grades. LOL. Also spring will delay braking application according to trailer’s GTW with deceleration of its vehicle. The following if you want better control of your trailer brake & still use engine brake; (not cheap but probably less then mishap & no springs) (battery with breakaway switch make a good safety feature) Carlisle electric-hydraulic brake system; http://www.carlislebrake.com/spec_tbp.html ElecDraulic report; http://bulktransporter.com/mag/transportation_elecdraulic_systems_provide_2/ Marketing manufacturing for ElecDraulic product; Ask for ElecDraulic system. Not shown on website. http://www.bludotinc.com/products.html Air/Hydraulic without ABS; http://www.bludotinc.com/pdf/th_series.pdf Electric brake; (that what I uses) http://drawtite-hitches.com/brake_controllors/brake_controllers.htm Important suggestion to newbie; Above all drive in controlling matter. Anytime a good drivers in command of heavy or light vehicle with or no trailer is to traveling only as fast as you can safety bring it completely to stop. Another word travel slower downhill. I hope I would heed to that….I’m not perfect. FWIW Sojourn for Christ, Jerry Jerry | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Would it be possible to wire the Jake (or retarder) on-off switch in to the 'reversing' solenoid circut so that the surge brake feature is disabled whenever the Jake (or retarder) is activated. It would also need a overide to re-activate the surge brakes if the tow vehicle service breaks are applied. This way it could function with out having to remember extra steps. I already have enough to forget with out adding more to the list :^) Just a thought, kyle4501 | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Kyle, it might be doable but it's not as easy as turning the reversing solenoid off and on. When you turn the solenoid on, it relieves pressure in the brake system completely, this also means that the actuating cylinder goes to it's fully compressed position. It's just like shooting a spring loaded pellet gun... it needs to be recocked before it will work again...hence... Say you are going down hill with jakes on and you turn on the solenoid. The trailer brakes release. Now you turn the solenoid off and apply the bus brakes... since the trailer's master cylinder is already fully compressed, there's no way for it to create braking pressure until it has been released at least once to "re-cock" itself. This means that unless you step on the gas at least once, hard enough to make the bus pull on the trailer, the trailer brakes won't work even with the reversing solenoid de-activated. This is usually something you wouldnt want to do on a grade! So simply adding switches to make the solenoid go on and off with the jakes won't really work unless you also learn to do the gas pedal dance. Not a simple solution. I am beginning to think that surge brakes might not be such a good choice for a highway trailer where long grades are involved. There are some other issues as well... regulations state that you must have some sort of breakaway mechanism that applys brakes if the trailer gets away from you... with the surge system this is easily accomplished with a trip-wire affair. With electric brakes this means having a charged battery on board to activate them... not my first choice. So even though I've asked this question about surge brakes, here's what I did on my trailer- it's two axles, so I simply put a surge brake on one axle and electric brakes on the other. The surge brake system takes care of the breakaway rule without needing a battery, and it also allows anyone to tow the thing around town without having to put in an electric brake controller. On the highways I disable it with the reversing solenoid. The electric brakes are hooked to the bus's brake light system and they get used on the highway when the bus brakes go on. Down grades isn't a problem with the electrics because they are off unless I step on the brake pedal. Best of both worlds I guess... the trailer supply folks thought I was pretty weird for doing this, but other than figuring out that surge brakes should be disabled on the highway, it seems to be doing well for me. | ||
| kevin schooler (Sylverstone_pd4501864)
Rating: N/A |
i have yet to tow anything with my scenicruiser, as i'm still sorting out building a hitch (repowering first) however, i have over 50,000 towing miles on my 89 dodge b250 van, that has a tag axle and air bag suspension, ( http://www.sylverstone.com/sca/images/war_wagon/war-wagon-005-side-01.jpg ) towing a custom pop top gypsy wagon trailer that i built to haul gear and so on for medieval reinactment events i do. the van weighs in at a bit more than 4k. 6k when i'm full up with people. the trailer weighs in fully loaded at 10,000 lbs, and has triple 8,000 lb axles under it. it's a bumper pull. i don't have any trick load leveling or anti sway hitch gear. i'm using a tekonsha prodigy ( http://www.tekonsha.com/prodig.html ) brake controller, and it works awesome. tounge weight is about 2000 lbs, and i use engine braking for downgrades. when i put on the brakes in my rig, the trailer brakes come on at whatever force i adjust in. the controller allows 3 boost levels, which is "how much power do i apply when you touch the brake pedal" ... and it has a manual brake lever as well, so i can apply trailer brakes only, should i choose (takes out sway like nobody's business) they say it pretty well here: First it must be understood that in an ideal situation the tow-vehicle brakes should stop the tow vehicle and the trailer brakes should stop the trailer. However the trailer brakes should provide a little additional drag on the hitch to help keep the combination straight. This is especially important at the beginning of braking. Next we must take into consideration that the braking effectiveness of tow-vehicles and trailers can vary extensively, and that there needs to be some variability and control in the application of the trailer brakes. Because the Prodigy is an accelerometer-based control it delivers power to the trailer brakes based on the deceleration it senses. Without boost this means that the tow-vehicle brakes have to initiate the braking for the combination of tow-vehicle and trailer. This works well with lighter trailers, however with a heavy trailer this puts an excessive strain on the tow-vehicle brakes. One of the functions of boost is to eliminate this condition. When a boost setting is used, the Prodigy applies a minimum output to the trailer at the onset of braking to initiate deceleration. The level at which the power knob is set, determines what that initial output will be. Boost level 1 generates about 13% of power set for the first 2 seconds and boost level 2 and 3 generate about 25% of power set for the first 2 seconds. All levels reduce by 50% after 2 seconds when the braking system is generating enough deceleration of its’ own accord. The remaining function of boost is to accommodate for the variables in the tow-vehicle and trailer brakes due to respective weights, number of axles, etc. Boost levels 2 and 3 each provide higher sensitivity to deceleration. This helps compensate and balance the braking between tow-vehicle and trailer. The final setting is done by feel. The driver should not feel that the trailer is pushing him, or experience over-aggressive trailer braking. I usually don't bother with touching anything while coming downgrade. i'm letting the engine braking do the work, as the tounge weight is pretty heavy on the downgrade (someone here is an engineer and they can explain it  ) so while the trailer is trying to push me around, i'm not really going anywhere. the tires on the van are 305/50/r15's and i've got 4 of them, and the tag axle center is about 18" in front of my hitch ball, so the trailer doesn't have a lot of leverage on me. i'm usually running boost 3, and if i hit the brakes lightly it will slow only the trailer, and a light *tap*tap*tap* on the pedal will let the trailer brakes do their thing without the van brakes even coming on. the manual brake lever will allow me to put on the trailer brakes as hard as i want as well, so it's very flexible. my only complaint about this controller is that it learns grace. i.e. once you adjust it (easy, from the drivers seat) it will use it's own circuts to do "the best job it can" and it learns... so after a while you can't feel the trailer at all unless you stomp the brakes. i find it a bit creepy my cruiser is going to be pulling the same trailer, and i'll be using the same controller, i'm very very happy with it. my question here is why the stress out about this? if i'm coming downgrade at 20 mph in my cruiser (22,000 lbs on the rear axles) a 10,000 lb trailer that i'm towing doesn't need brakes at all unless i get into a runaway condition (lose a gear, can't grab the next one, jakes don't work, heat up the air brakes and lose them) ... and in any of the above cases, i want every damnned bit of braking that trailer can do, because the less speed you leave the road at the more likely the k rail is going to stop you, or the less likely whatever you hit is going to kill you. surge brakes are dangerous, and no longer legal in a lot of places, i can't see why anyone would want to use them anyway, as they are, for the most part, a pain in the butt. -dd | ||
| Sojourner (Jjimage)
Rating: N/A |
The reversing solenoid is only an open & close inline valve between surge cylinder & wheel cylinder hydraulic line. Purpose to close valve while on level ground to achieve neutral line’s pressure before backing up. Another word it serve no purpose but for backing up. Or you will have problem for any other purpose. So, forget ever using reversing solenoid to release hydraulic pressure while downhill driving. It will not happen. To fix the problem is either adds heavy spring to keep it from activating surge cylinder pressure until overcome spring pressure. You have to work that out or go to electric/hydraulic system. FWIW Sojourn for Christ, Jerry | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Actually the reverse solenoid I have is a 3-way type that opens up the entire system to the reservoir and releives all pressure in the system. From the Champion Trailer website: " It may occur that you will have a partial activation of the surge brake coupler due to the compressive forces being applied between the tow vehicle and the trailer prior to backing up. This may drastically impede your ability to back up a hill. If this occurs you may want to convert your reversing solenoid to a bleed type solenoid valve. With a bleed type solenoid valve, whenever the solenoid is activated, all fluid pressure in the system is dumped back into the reservoir. This is the preferred solenoid valve if backing uphill is one of your towing considerations." So Jerry, it will definitely serve to "turn off" the surge system IF you have this type of solenoid. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
I wonder how U-HAUL solves this problem? They have surge brakes on all their two axle trailers. I have never had any complaints about people not being able to back up. Richard | ||
| Sojourner (Jjimage)
Rating: N/A |
Your absolute right, Gary using 3-way solenoid valve via having it bleed to reservoir. Better yet but still no pump-up to recycle during downhill until it begin to pull. DML….I rent large U-Haul w/tandem hydraulic axle using Oldsmobile Silhouette from Fl to Mi. No problems as long I momentary apply car brake to reduce speed until 10 mph less then release. Repeat as long it gaining speed but not ever drag your brake. Car & trailer in this case happen be nearly equal rolling resistant to prevent trailer’s dragging. There was no problem backing & no solenoid. That was three years ago....maybe have them now?? FWIW Sojourn for Christ, Jerry | ||
| Kyle Brandt (Kyle4501)
Rating: N/A |
Well, I guess I should have realized that there are many different surge brake systems out there. The only ones I have seen were; 1) a u-haul with drum brakes & no solenoid that backed up just fine on flat pavement, but not so good backing up a steep driveway. 2) a home made unit that included a unique linkage between the coupler & brake master cylinder that allowed the brakes to be deactivated & reactivated while under way. Everyone that used it said it was great (The guy that made it was a stationary diesel mechanic, built custom hot rods as a hobby (several made it into the hot rod magazines), & was a fan of Rube Goldberg(sp?) machinery. I wish that I had paid more attention to his setup so that I could explain it better. It seems that the electric brakes are the easiest to work with while under way. | ||
| Johnny Rating: N/A |
My car trailer has surge vrakes--to back up a hill, there is a pin that goes in the hitch mechanism, to physically prevent the brakes from activating. | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
I chose the spring size and number for my cars surge brake built into the towbar baseplate by having my wife drive past and checking the action. I had to reduce the springs tension a little so it activated quickly enough. We drove many steep downgrades with the Jake on and the car brakes never heated up at all. You can shoot the temp with an IR non contact thermometer to see if the trailer or car brakes are dragging. I don't believe the surge brakes should apply with only slight braking by the towing vehicle. They may lock up with a hard appllication if they are that sensitive. |
