Jake brake on or off driving on flats or small hills?

[holstein13]

One of the debates we had this week was whether you should drive with your Jake Brakes on or off while on flat land or small hills. Everyone agreed that you should use them in the mountains or steep grades.

But what about hills and flats? The tire and brake instructor said we should not use them because the brakes need a workout to prevent glazing and if you always use the Jake Brakes, you won't automatically adjust your slack adjusters.

The engine guy said that the latest evidence from Cummins suggested that the Jake Brakes helped keep the turbo chargers clean. He recommended leaving it on.

Do any of you have an opinion?

[holstein13]

JackMS wrote:
Good to know powerspec works with inline 5. The powerspec website i saw says you need inline 6 which is much more expensive.

Yes, not only does it work, but it's fully supported by PowerSpec tech support at Cummins. When I had a driver problem, Cummins logged into my computer and updated my flash memory in the inline 5 and made sure it all connected to my engine. They were very helpful.

[JackMS]

Good to know powerspec works with inline 5. The powerspec website i saw says you need inline 6 which is much more expensive.

[holstein13]

UPDATE: I received the Inline 5 interface kit for my engine port and ECM and I downloaded Cummins PowerSpec program. It all worked like a charm and I made the suggested changes to the Jake Brake. I really love the way the Jake Brake operates now. Thanks to all who responded to this post.

[holstein13]

NeverHome2 wrote:
Holstien13, When we first got the coach I took it to Cummins for reprogramming. They found that the program didn't change the way it operated so they called Holiday Rambler who said that it is wired to operate the way it is.

I called HR to get a wiring diagram and ask for help. They said they could not tell me how to change it for safety/legal reasons and the diagram they sent was a point to point wire map not a ladder/logic diagram so it is hard to figure out. It remains the way it is.

I'll find out soon enough. I went ahead and ordered the interface kit for the engine port and ECM. I'll download Cummins powerspec program when I get it and see what I can change.

[NeverHome2]

Holstien13, When we first got the coach I took it to Cummins for reprogramming. They found that the program didn't change the way it operated so they called Holiday Rambler who said that it is wired to operate the way it is.

I called HR to get a wiring diagram and ask for help. They said they could not tell me how to change it for safety/legal reasons and the diagram they sent was a point to point wire map not a ladder/logic diagram so it is hard to figure out. It remains the way it is.

[nemo45]

Mr.Mark wrote:
On our previous coach (Dynasty), I used it whenever we started to coast too fast and also to slow down in normal traffic. The cruise would not work if the jake was turned on so I kept it off until I needed it. The Jake would kick off at about 20 mph or so and then you had to use the service brakes.

We have a 6 speed retarder on the new coach.

MM.

Also on mine the jakebrake will not work with the cruise on. I like to use the jakebrake in town where there are stop lights. Makes it much easier to stop for a quick light change.

[holstein13]

NeverHome2 wrote:
Computers introduced cruise control that worked with the Jake and would automatically start the Jake and control your speed to 5 mph over setpoint of the cruise. I so wish my motohome worked the same way. Our HR turns off the cruise when you turn on the exhaust brake and when you turn off the exhaust brake you have to reset the cruise. Never have I seen anything so stupid.

What engine do you have in your HR? If it's a Cummins, you can probably reprogram the settings for the Jake Brakes and cruise control using Cummins PowerSpec (available for free to all owners).

[creeper]

DSDP Don wrote:
"creeper".....I give up! Between the two posts on this subject, you appear to be the only one that just doesn't get it. Just can't fix that!

You should give up, you're just plain wrong on brake glazing. It's really a simple concept, but full of myths and wives tales.

Ditto Neverhome2, drove my truck with the jake brake on 100% of the time. Never glazed a set of brakes and never had any issues, although I was a bit lighter then you. 🙂

[NeverHome2]

Wowww! So many opinions about Engine and Exhaust brakes. I know many drivers of trucks now drive motorhomes but I used Jake Brakes (engine brakes) on Cummins engines since 1970. They never harmed an engine, and saved so much brake use, and raised the safety level and made the driver much more comfortable about long descents. Before we had computer controlled engines the clutch, brake, throttle and dash switches controlled the operation of the Jake brake. I never turned it off full use. It was so handy when stopping 80,000 lbs. Just take your foot off the throttle and instantly the jake came on, but when idling if you left it on it would stall the engine.

Computers introduced cruise control that worked with the Jake and would automatically start the Jake and control your speed to 5 mph over setpoint of the cruise. I so wish my motohome worked the same way. Our HR turns off the cruise when you turn on the exhaust brake and when you turn off the exhaust brake you have to reset the cruise. Never have I seen anything so stupid.

[DSDP_Don]

"creeper".....I give up! Between the two posts on this subject, you appear to be the only one that just doesn't get it. Just can't fix that!

[creeper]

DSDP Don wrote:
"but you can also polish the brakes by applying them lightly on a regular basis.

HUH? Polish the brakes? What kind of hocus pocus is that?

Your engine/exhaust brake typically drops off at 15mph. Since most RVer don't rush up to signals, they need very little braking to slow the coach to a stop or slow roll after getting down to 15 mph.

Exactly and that's when you work the brakes and the adjust the slack adjusters.

Many think they're saving those expensive brakes when they're really lightly glazing them.

Non sense.

The repair is a high speed run with a few hard stops. You can also use emory cloth to clear up this type of light glazing.

We'll you're half right, nonsense on the first part urban legend. To remove glazing I prefer a angle grinder with a an abrasive disc. It's much faster and efficient then emory and you can round the edges to prevent squealing.

The high heat glazing that you're speaking of takes rotor/drum turning and shoe/pad replacement. There are levels of glazing!!!!

Glazing is caused by HEAT period. Your brakes when used cause dust, when you over heat your braking system that dust turns to glaze. Glazing is cumulative over time. Thinking a couple of high speed runs will remove glazing is just an urban legend. There is only one way to remove glazing.

[holstein13]

DSDP Don wrote:
"Creeper"....It's lovely that you drive the mountains and know all about heat glazing, but you can also polish the brakes by applying them lightly on a regular basis. Your engine/exhaust brake typically drops off at 15mph. Since most RVer don't rush up to signals, they need very little braking to slow the coach to a stop or slow roll after getting down to 15 mph. Many think they're saving those expensive brakes when they're really lightly glazing them. The repair is a high speed run with a few hard stops. You can also use emory cloth to clear up this type of light glazing.

The high heat glazing that you're speaking of takes rotor/drum turning and shoe/pad replacement. There are levels of glazing!!!!

DSDP Don, I thought that polished brakes are exactly what rotors are supposed to look like. Correct me if I'm wrong, but every single disk rotor I've ever seen on every single car has polished rotors with concentric small groove marks when they are used. On my home vehicle, it gets rusty when I don't use it for a while, but after a trip out, it returns to a normal relatively mirrored polished finish. Frankly, I don't see how it's possible for the rotor to look any other way unless there is some serious metal on metal scratching going on.

Please help me understand this. Aren't your brake rotors shiny and mirrored? What am I missing here? Again, this is an area I don't really understand well.

All my research suggests that glazing is a result of over-heating the brakes. How can applying them lightly cause overheating unless you ride the brakes lightly and constantly, which I don't think Creeper is advocating?

The amount of braking needed to slow from 15 mph to 0 is negligible and only for a short amount of time.

[DSDP_Don]

"Creeper"....It's lovely that you drive the mountains and know all about heat glazing, but you can also polish the brakes by applying them lightly on a regular basis. Your engine/exhaust brake typically drops off at 15mph. Since most RVer don't rush up to signals, they need very little braking to slow the coach to a stop or slow roll after getting down to 15 mph. Many think they're saving those expensive brakes when they're really lightly glazing them. The repair is a high speed run with a few hard stops. You can also use emory cloth to clear up this type of light glazing.

The high heat glazing that you're speaking of takes rotor/drum turning and shoe/pad replacement. There are levels of glazing!!!!

[creeper]

WILDEBILL308 wrote:
This is true Glazing is more associated with over heating. I haven't heard of anyone wearing out their brakes on a diesel pusher.
Bill

Wearing out a set of brakes on a diesel pusher is rare if you're the original owner and/or a gas coach. It's more like that the 3rd or 4th owner might.

Your brakes get plenty of exercise in stop and go traffic stopping 30k pounds, just pulling into a campground will adjust your slack adjusters. I drove hazmat trucks, which are similar in size to Motorhomes. We wore out the trucks before the brakes and we drove with the jakes brakes on 24/7. Never an issue. The last thing you want in a Hazmat truck is to heat up your brakes and have them go away.

Heat is the enemy, not jake brakes and why chassis makers have big cooling scoops directing cooling air directly on the brakes, Ford had nice big ones on the F-53 chassis.

Just pulling into a campground will adjust a slack adjuster.

Just a note on squealing, this can be caused by damaged rotors caused by excessive heating. In that case you'd need to have them resurfaced. Drilled and slotted rotors is what they came up with to prevent excessive heating. Another cause is the wearing of brake pads and pad gunk building up around the pads.

The pads will wear and have 90 degree edges. To fix it you just need to grind the edge of the pads to a more rounded edge. Occasional slow braking will not fix or prevent this. It's more the design of the pads and it's composition. Semi metallic pads are more prone to do this and newer pad composition really prevents now vs. the past.