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04-19-2014, 07:48 AM
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#1
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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UHaul surge brakes
Brakes locked, started smoking...released some fluid so I could continue the trip. Has anyone dealt with servicing the unit?
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04-19-2014, 08:26 AM
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#2
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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This sounds like the master cylinder actuator has lost it's freeplay and the piston can't back up far enough to allow fluid to flow back after pressure is released. Can be as simple as putting more free play in that linkage or something (even dirt) jamming the hitch linkage itself. Less probable is an internal problem with the master cylinder. It's a simple system that any brake shop can troubleshoot and solve.
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04-19-2014, 01:33 PM
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#3
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Senior Member
Name: Ron
Trailer: Trillium 13 ft (green grape)
Ontario
Posts: 442
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Have you checked to make sure the manual emergency brake is not in the locked on position ?
RRJR
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04-19-2014, 03:07 PM
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#4
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Senior Member
Trailer: 16 ft U-Haul VT
Posts: 2,866
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Kevin rebuilt ours. Our VT had incomplete brakes when we got ours. I found a used Uhaul surge gizmo on ebay. He bought drums online. Then he worked with Uhaul (I think - not sure) to find the right wiring. They work now; nice soft stop.
I will tell him to check this thread out.
CindyL
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04-19-2014, 04:29 PM
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#5
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Senior Member
Trailer: Bigfoot Silver Cloud -1988
Posts: 1,539
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I found a surge brake actuator tool on eBay that let's me "pump" the piston easily by myself. I used this to bleed the brakes after I got them all installed (new backing plates and shoes on both sides). I also put a new clamp on the rubber boot to hold it secure. Finally, I pumped that hand brake actuator lots of times to make sure the piston moved smoothly. I don't remember doing any adjustments to the piston actuator itself but there might have been an adjustment nut there. Anyway, our brakes are working very nicely now and I just adjust the pads every spring and check again mid-season.
If they do lock up, you can loosen the pads using the adjustment star on the back of the plates. Loosen it until the pads back off the drum.
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04-19-2014, 08:01 PM
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#6
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Senior Member
Name: bob
Trailer: 1996 Casita 17 Spirit Deluxe; 1946 Modernistic teardrop
New York
Posts: 5,413
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Any hydraulic brake that has some age on it or doesn't get used much can be subject to corrosion in the master or wheel cylinders causing them to stick or seize. Brake fluid tends to attract water. There is debate among vintage car owners that I won't get into about the benefits of using silicone brake fluid. I have several vintage vehicles and have dealt with this problem many times. As a last resort, if the cylinders can not be replaced due to unavailability of parts, or can not be rebuilt because of pitting, there are places that will bore and sleeve them.
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04-20-2014, 08:24 AM
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#7
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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Quote:
Originally Posted by Kevin A
I found a surge brake actuator tool on eBay that let's me "pump" the piston easily by myself. I used this to bleed the brakes after I got them all installed (new backing plates and shoes on both sides). I also put a new clamp on the rubber boot to hold it secure. Finally, I pumped that hand brake actuator lots of times to make sure the piston moved smoothly. I don't remember doing any adjustments to the piston actuator itself but there might have been an adjustment nut there. Anyway, our brakes are working very nicely now and I just adjust the pads every spring and check again mid-season.
If they do lock up, you can loosen the pads using the adjustment star on the back of the plates. Loosen it until the pads back off the drum.
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Kevin, Can you post a pic of the actuator tool?
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04-20-2014, 08:26 AM
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#8
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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Quote:
Originally Posted by mary and bob
Any hydraulic brake that has some age on it or doesn't get used much can be subject to corrosion in the master or wheel cylinders causing them to stick or seize. Brake fluid tends to attract water. There is debate among vintage car owners that I won't get into about the benefits of using silicone brake fluid. I have several vintage vehicles and have dealt with this problem many times. As a last resort, if the cylinders can not be replaced due to unavailability of parts, or can not be rebuilt because of pitting, there are places that will bore and sleeve them.
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OK, so the culprit is likely the master cylinder since BOTH brakes locked.
I will follow up, thanks
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04-21-2014, 08:12 AM
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#9
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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Not Applicable...
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04-21-2014, 08:33 AM
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#10
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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Quote:
Originally Posted by Kevin A
I found a surge brake actuator tool on eBay that let's me "pump" the piston easily by myself. I used this to bleed the brakes after I got them all installed (new backing plates and shoes on both sides). I also put a new clamp on the rubber boot to hold it secure. Finally, I pumped that hand brake actuator lots of times to make sure the piston moved smoothly. I don't remember doing any adjustments to the piston actuator itself but there might have been an adjustment nut there. Anyway, our brakes are working very nicely now and I just adjust the pads every spring and check again mid-season.
If they do lock up, you can loosen the pads using the adjustment star on the back of the plates. Loosen it until the pads back off the drum.
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I used to work in a service station (old time name for Gas Station when they also had a garage & mechanics) where we rented utility trailers. The double axle ones had surge brakes on one axle.
To bleed them we would block the back side of all four wheels, hook it up to a truck and back up against the blocks several times and, with pressure against the blocks, open the bleeder fittings. As I remember, it took about 2-3 cycles on each side and it was done.
But, ya gotta remember, this was back in he day when we just clamped a "Bumper Hitch" onto the bumper and off they went.
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04-21-2014, 08:55 AM
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#11
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Senior Member
Name: bob
Trailer: 1996 Casita 17 Spirit Deluxe; 1946 Modernistic teardrop
New York
Posts: 5,413
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I would pull it all apart and check everything due to the age of the trailer. At that time check the wheel cylinders for leakage and see if they are stuck. Just pull the rubber boot back to check for leakage or corrosion in the wheel cylinders. You can get a cheap master cylinder bleeder kit where you can just bleed it with the line disconnected. I would replace the fluid, again it's old stuff, probably time for a complete overhaul and get it all back up to new condition. Simple vacuum bleeder kits are not too expensive, I have one, plus a pressure bleeder.
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04-21-2014, 10:49 AM
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#12
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Senior Member
Trailer: 16 ft U-Haul VT
Posts: 2,866
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Kevin will get back to you. He said he could post an image. Busy right now with end-of-the-year crazy students.
But yeah, I think I just ordered a replacement front seat for our Eurovan that was broken when we bought it. Getting ready for a season of camping.
CindyL
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04-21-2014, 01:51 PM
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#13
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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Quote:
Originally Posted by CindyL
Kevin will get back to you. He said he could post an image. Busy right now with end-of-the-year crazy students.
But yeah, I think I just ordered a replacement front seat for our Eurovan that was broken when we bought it. Getting ready for a season of camping.
CindyL
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Thank you,
AP
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04-21-2014, 07:02 PM
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#14
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Senior Member
Trailer: 16 ft U-Haul VT
Posts: 2,866
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Here Ami.
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04-21-2014, 08:51 PM
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#15
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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Quote:
Originally Posted by CindyL
Here Ami.
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Much appreciated, Ami
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04-22-2014, 07:26 AM
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#16
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Senior Member
Trailer: U-Haul VT16 1985
Posts: 110
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What is the function of the chain?
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04-22-2014, 08:17 AM
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#17
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Senior Member
Trailer: 16 ft U-Haul VT
Posts: 2,866
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I will give Kevin the heads-up to respond tonight. I don't know what the chain was for. I do remember working this gizmo with him; it may have just hung there.
Notice that our VT does not have the original brake mechanism (Sorry, I don't know the technical terms.) though. I found a used on on ebay and spent part of my grandmother's inheritance purchasing it. I am not sure that will make a difference in your work, Ami.
CindyL
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04-22-2014, 10:43 AM
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#18
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Senior Member
Trailer: Bigfoot Silver Cloud -1988
Posts: 1,539
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I think this hand tool was made for a variety of surge brakes. I'm guessing the chain and pin was for some other application (lock pin for the piston?). I really don't know what the chain is for. I didn't need it for anything.
The surge unit CindyL is referring to on our VT is not the original unit. She bought a 2nd one on eBay and it is slightly different than the original. We got it thinking the first one didn't work, then discovered it did work. Now we have two!
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