Braking

[bluflame11]

I have something I wanted to ask about...i have tried searching and I have not found it, or I'm not searching the right terms...i have a 2007 Volvo 730, still tandem. We tow a 42 foot fiver. Yesterday we had a scary situation. We were driving along an interstate with about 4 lanes of travel. I was in the second lane from right. We were probably going 45mph as there was traffic. Suddenly the Lange I was in came to a dead stop. I jumped on the brakes. The tandem locked up but the fronts did not. Thankfully, no one was beside me, so I was able to steer to the slow lane to avoid a collision. 

Since then I have been wondering if my brakes are working as expected? I have a direct link for the controller. I have the understanding that the Brakes are proportional, so I have the trailer air supply lines capped and always run with the red octagon on dash pushed in. Am I doing something wrong? Did I not step hard enough? Should I leave the red octagon out? It worried me because one of the big reasons I went hdt was for panic stops and now I'm second guessing that....

Thanks inn advance!

[GlennWest]

Interesting. In a panic stop my truck does not lock down. I have abs. Now my Teton does. It will lock down all three axles. Now I have air over hydraulics.

[maveric]

The red line should be to supply air to the trailer. Are your trailer brakes air/hydraulic, or straight air? If they are electric, you shouldn't need to do anything with the red. Same as if bobtailing. 

Are your truck brakes adjusted? You don't want the fronts to lock up so you can steer in a skid, but they should still be adjusted periodically. 

[Darryl&Rita]

Time to do some trouble shooting. Your truck should have ABS, that should have prevented the rears from locking up. Your trailer brakes should have helped with the braking. You need to lift your chin, and look further forward. This last part is imperative.

[GlennWest]

That is why I posted. I don't have a direct link but my truck does not lock up. All modern trucks have abs and should not lock. I will add my truck stops better with my Teton in tow. 5 axles braking vs 2.

[Nigel]

Check your brake adjustment.  Everyone driving a HDT should no how to do this and should be checking regularly.  Commercial drivers are supposed to do it daily and are not allowed to move if they find a brake out of adjustment.   Automatic slack adjusters do fail that is why they sell replacements.

I’ll  get off my soapbox now.

Nigel

 

[Parrformance]

My abs does not work, and in quick stops especially when bobtailing the tandem will lock. I suspect that you are ABS is not functioning.

Edited October 17, 2020 by Parrformance
Spelling correction

[billr]

Like said check slacks , maybe get brakes inspected by a tech. I had glazed front  drums and cracked shoes years ago , not long after we bought the truck. I had nothing to compare it to. But after replacing everything it was a new truck stopping. 
 On our truck with trailer connection plugged I prefer the feel of the brakes with trailer brake knob in all the time.  I don’t like at all with it out. I feels like I’ll never slow down. Tractor protection valve. 
 

That being said, I always try to never need the brakes allow that space to let the Jake do the job. 

[bluflame11]

I just had the rears adjusted. My brakecontroller sores not use air at all...it is totally electric. How do I check the abs?

[noteven]

The ABS light should illuminate on start up indicating system self check, then go out. The light should stay on if there is a malfunction. 

Describe the "lock up" you experienced.... 

Class 8 ABS brakes are very powerfull when you stand on the foot valve pedal in an emergency. There will be activity when the ABS is activated under full braking effort. 

[dlcarsonak]

   In the mid-1990's Volvo started installing a Bob-tail system. (not the correct name) With the trailer (red) button in it things the truck is loaded and puts more air to drivers. With the trailer button out it applies air equally to steer and drive. Go to a empty parking lot and practice stops both ways.

[Jim & Wilma]

13 hours ago, billr said:

 . . . maybe get brakes inspected by a tech.
. . . I always try to never need the brakes . . . 

Don’t remember ever paying someone to work on any of my vehicle brakes over the years or change oil for that matter. That changed with our HDT.  
 

I routinely inspect our brakes but also include them in our annual shop maintenance when we have the oil changed. The mechanics experience along with pit/lift inspection access, is worth the small expense, IMHO.

I also “play the game” of seeing how little I have use the brakes. The Volvo I-shift stalk makes that remarkably easy, once you figure out how to use it. 

[Parrformance]

22 hours ago, noteven said:

The ABS light should illuminate on start up indicating system self check, then go out. The light should stay on if there is a malfunction. 

Describe the "lock up" you experienced.... 

Class 8 ABS brakes are very powerfull when you stand on the foot valve pedal in an emergency. There will be activity when the ABS is activated under full braking effort. 

I found out about my non-working ABS function from a mobile tech that was diagnosing my no start condition.  I have no ABS light on the dash illuminated.  The tech said "your ABS is not working".  The wife and I were traveling, and did not feel The need to try and fix this issue on the side of the road, so we did not investigate it further.

The previous owner, had installed the forward drive axle, perhaps when this was done the tech turned off the ABS warnings?

While looking into the fan clutch electrical fault, I came across the two different fuses for ABS, the 30 amp fuse is installed and checks good, the 10 amp is missing.

When I get home I will replace this fuse, I suspect I will receive an ABS light, and maybe a error code.

Edited October 18, 2020 by Parrformance
Added info

[GlennWest]

Interesting. Does just 1 axle lock down? If so it needs sensors.

[bluflame11]

I know the rear slid....I'm not sure whether it was both axles or just one. The abs light does come on and go out at start up. I hear several series of "clicks" when you first turn on the key that I had always thought was the abs testing itself, but I may be wrong about that. As far as using the transmission to slow down, I do that as much as possible, but being a 2007 truck, it is pre I-shift. I have the Eaton 10 speed ultra shift. Makes it a bit harder. 

[GlennWest]

On my old Freightshaker, when I singled, no abs. Had to change to a 4 axle box. If I added back an axle I would still have 4 wheel abs. So front axle would lock. Don't know about your truck abs though

[jenandjon]

12 hours ago, GlennWest said:

On my old Freightshaker, when I singled, no abs. Had to change to a 4 axle box. If I added back an axle I would still have 4 wheel abs. So front axle would lock. Don't know about your truck abs though

How hard is that to do? Where is the box located? My freightliner was singled by the previous owner. I get a no abs message when I start it. I guess I just never worried about it.

Edited October 18, 2020 by jenandjon

[GlennWest]

Not hard at all. Freightliner offered both 6 axle and 4 axle so both boxes are on the market. I got a used one on a truck used parts site. Don't remember site though. Simply unmount box and install other. Remove the extra abs cables if they still there. Mine is underneath on passenger site railing. 

[GlennWest]

 

 

[jenandjon]

Thanks Glenn. The guy that singled it is helping me do some wheel seals this winter. We should be able to figure this out now.

 

Sorry I didn't mean to hijack the thread.