Front end wobble during braking on steep grades

[jordandvm]

We recently finished a 30 day RT from Oregon to Kansas and back, crossing over the Rockies both directions while the weather was good. While going down the steep grades of Vail and Monarch Passes, I experienced a severe wobble in the front end that shaked the whole tow vehicle when braking to slow down. This occured even when I’m downshifted into 3rd gear (automatic transmission). I try to keep my speed below 60 mph while descending steep grades. This is not the first time this has happened. It also occurred on other steep grades on other trips. But it doesn’t happen consistently on all grades.

Before leaving on the trip, I adjusted my Prodigy Voyager brake controller according to the manual instructions to see if it would negate the problem. It apparently didn’t help. I also rotated all the tires and rebalanced them before leaving. I don’t think I have any front end alignment problems, because it only happens on steep grades.
I’ve been concerned about the Prodigy Voyager being the right brake controller for my current 28’ CCD. I’ve been reasonably happy with it’s performance on trips. It was the original brake controller when we started with our 22’ CCD. I‘m thinking about upgrading to the Prodigy P3 controller. I don’t know whether this will make any difference in the wobble during steep descents, but I think I’ll have more peace of mind in ease of adjustment to get the right setting for the 28’.

Any thoughts on what’s causing the front end wobble? Has anyone else experienced this with their TV on steep descents?

Should I consider upgrading my brake controller?

Thanks

[3Ms75Argosy]

Hi Jim! A couple of possiblities... the first is that you're front brakes are heating up when descending, causing them to warp or shudder. I'm surprised it went away however, as usually, once they warp they stay warped (and you feel a pulsing in the brakes always when braking). So some other thoughts... you might want to get your brakes checked.. is it perhaps the ABS kicking in? I severely overheated my brakes going 40 mph while geared down one summer coming into Kelowna BC... it's pretty easy to do with these drum brakes. I do figure to upgrade to disks when I eventually get around to changing the axles on the Argosy.

That said, you might need to change the rotors in the front. I believe Brembo makes a rotor that's supposed to be pretty tough.

I'm not sure if the controller is the issue....
Marc

[ROBERTSUNRUS]

Hi, sounds like warped front brake rotors to me. Going over the rockies on my last trip I felt a bit of brake shudder on my tow vehicle too, but at slower speeds I don't feel it. As for brake controllers Voyager, Prodigy, and P-3 are the models and Tekonsha is the brand name. My trailer came with the Tekonsha Voyager. The Tekonsha Prodigy is said to be a great brake controller. I chose the Tekonsha P-3 when I decided I wanted to upgrade my brake controller. I like the P-3 for how it works and ease of making adjustments.

[2airishuman]

hi jim

i agree x3 check the tv brakes.

reads like warped rotors but loose calipers might also be at issue or pads that are gunk'in up the rotors.

now the t.b. controller may ALSO have something to do with this...

IF it's not adjusted to activate soon enough or with enough vigor,

THAT issue could put more stress on the front disc of the tv.

front suspension bits might also be the issue so have that checked too...

but a brake issue seems most likely.

see ya in the spring!

cheers
2air'

[ticki2]

To add to the list , check for rust on the inboard side of the front rotors.

[68 TWind]

I looked through your images to see if I could tell what your TV is. Saw an Avalanche . Chevy has had a lot of problems with warped front rotors in the past ( I have a Tahoe and have put 3 srt on it the past 8 years). Do not let a shop "turn" your rotors. Yes there may be enough metal left that they will be in spec but you loose mass and therefore head sink ability. Turning is a very short term solution and because you are towing, you need the best new rotors you can get. Yes Auto Zone has cheap stuff, but I solved my Tahoe rotor problems with the best premium made in USA ( 2x the price) rotors that NAPA had. There are even better ones on the market that are slotted and drilled to help keep the cool, as are complete replacement of calipers and rotors with a high performance set. Your trailer brakes may be doing a fine job, but your TV is big. The heat generated slowing it down is tremendous and heat will cause them to warp and give you the vibration.

[boondockdad]

improperly torqued (tire service center using air hammer without torque extension) lug nuts can also cause this..

[overlander63]

The vibration is from your front brake rotors having become warped. You feel it more when things have warmed up because the heat makes them temporarily even more warped. You will need new rotors and good quality brake pads. If the rear brakes are drum, they need to be properly adjusted to minimize the work the front brakes have to do.

[Bob Thompson]

I agree with the front brake rotors being cooked! It's called "brake judder" and a quick Google will give you a wealth of info. Best solution, top quality aftermarket slotted rotors, like say Brembo, and carbon metallic brake pads like Performance Friction available at Autozone. Be sure to seat in the new pads properly.

[richinny]

just to clarify things..........

are we talking about a "wobble" in the steering wheel or a wobble in the vehicle?

[Bob Thompson]

You would feel brake judder in both places, but only when applying the brakes.

[richinny]

the OP stated wobble. wobble to me indicates a less rapid vibration than judder so i was wondering if the tail wasn't wagging the dog.

[jordandvm]

Thanks all for your input!

The vibration I felt while braking was the steering wheel and whole front end of the TV.

The lug nuts were torqued after I had the tires rotated, so don't think that is the problem.

I will take the Avalanche to my local Chevy dealer and have them check out the rotors. At the last service (before the trip), they did say the brake pads had 60% left on them and didn't need replacing. I didn't know enough then to ask about the rotors.

As to the adjustment of the Voyager brake controller, I've never felt I've "dialed in" the best setting for my TV & trailer. The instructions were not describing what was happening when I changed the setting and applied the brakes while on a flat surface at 20 mph. I never experienced trailer brake lock-up, like the instructions said if you have too much braking. So there very well may be a problem with the controller not being set just right, and therefore when going downhill putting too much pressure on the front disc brakes warping the rotors. It all makes sense!

I'll get the TV brakes checked first. It's time to change trailer tires (5 years old), and I'll have the trailer brakes serviced as well at that time.
Then I'll purchase the P3 controller to replace the Voyager. Hopefully all of this will solve the problem!

Thanks for all your help!

[tphan]

Have to agree, sounds like rotors. I warped the rotors on my Sienna mini-van by towing a 2,000# pop-up trailer, without trailer brakes, down passes here in Colorado. I just had that front-end shake diagnosed, got new rotors, and now it brakes smoothly. The good news is that new rotors are not all that expensive!

[Mikethefixit]

I concur with the warped rotors. Seeing that the TV is the yr it is,I would consider taking those rotors off an scrapping them. DONT TURN EM.
When you take them off you will find an uneven wear pattern on the back side of the rotor. The inside pad is probably glazed and not braking at all.
If you can change the pads,you can change the rotors. Replace the pads with new metallic pads (best you can buy)and made in the USA rotors. I am very certain your problem will go away.
I recently did my sisters Explorer 4wheel drive with everything new ($155) and her problem same as yours, went away. They also pulled a camper,SOB with fold outs.
Good Luck and Be Safe NEW BRAKES are a good investment !

[Ag&Au]

There are some things to consider when towing a large trailer downhill. I recommend the boost 2 position of the Prodigy. The quick onset of braking helps ensure that the trailer stays behind the TV. In my opinion, 60 MPH is way too fast for the steeper parts of mountain passes. I try to find a gear and speed that will allow me to only occasionally brake, for instance when approaching a sharp curve. I do not exceed the speed that will allow me to shift into the next lower gear without braking or over revving the engine. If I am passing trucks, I use that as a trigger to evaluate what I am doing. If traffic prevents me from passing the slower trucks without exceeding a prudent speed, I just relax and stay behind them. I may get to the bottom later, but my chances of getting there are greatly increased. I am posting this because, if the brake disks are warped, the likely cause is overheating from overuse.
Regards,
Ken
P.S. Over a period of sixteen years, two brake controllers, three trailers and three tow vehicles, I have never been able to get trailer brakes to lock up.

[jump]

Slotted rotors were developed for racing and will cut into the pads causing the need to replace more often...

here's another thought/question: if the tail is wagging the dog, could that be caused by a pulsing in the brakes on the trailer?

[Bob Thompson]

I heard and read that when I purchased my slotted Brembo rotors. I know it is happening too! But with 80,000 miles (most of it towing my 25' Excella) on these rotors and pads and half the thickness of the pad remaining, I'm convinced it's not a problem I need to worry about for another 50,000 miles or so. I could take pics!

[HowieE]

I have to agree with the others that your rotors are warped. The fact that the problem comes and goes does not negate the fact that it is the rotors. The wheels will come and go in and out of phase with each other as you turn corners. This phase change will effect the severity of the wobble.

As for your controller. Most manufactures have a setup procedure that has you drive at about 25 mph and slam on the manual control, repeating this until just below the point at which the brakes lock. If you have preformed a similar setup your trailer should be braking enough to account for itself. Having warped the rotors I would think your controller is just set too low.

Another factor that all to many drivers fail to do is drive down a hill in the same gear you went up the hill. That is not to say the position of the shift selector while going up the hill but rather the actual gear the transmission has selected. You will have to pull the selector down manually to do this while going down a long hill. If you follow this rule you should not have to brake hard during the descent. You see this idea presented at the top of every hill for trucks. It is good advice for towed vehicles also.

[JStanley]

Jim, I experienced similar vibrations with my 2007, ¾ ton Suburban towing a 25ft Safari down hill on my way to the ’08 Alaskan Caravan. This was not an issue but a real problem with risks of further problems. After the Caravan and about 12,000 miles and with my Suburban still under warranty I took it to my Chevy dealer for service.

He knew about my trip and said that if the breaks are well worn then it is my fault. It could cost about $ 90 each. I said Okay; the problem must be fixed. Later he called and said that we’re having GM pay for this repair. Great! I asked why and what was the cause, but he didn’t say exactly.

Months later I explained the problem to a machinist and who designed machines that make machines. He said the rotors were probably “green castings,” and explained the process of machining, tempering and curing the surface area. Also went into detail about how metallurgy and the multi step process of rotor manufacturing and machining has evolved over the years.

So in my case it appears that “green casting” rotors were installed on my TV. The Chevy service rep didn’t say that, and he could have charged me $360 for it instead of GMC and I wouldn’t have known any better.

BTW: Jim, Do you remember we meet each other at Watson Lake, Yukon, on 7/20/08?