JK loss of brakes after ELBD very active

[SeaComms]

LOL - I bet that is it Yom, high revving motor = low vacuum = low brake assistance, couped with ELBD going crazy in the slippery mud up the hill using up all the available brake booster vacuum = no brakes.

Add an electric vacuum pump to chime in whenever vacuum drops to low to prop up the system and my problem is solved.

Now interestingly Chrylser Jeep US and Australia have still both denied any knowledge of the problem I described, yet have fitted an additional part to the 2012 models to fix exactly the problem I described??

I hear a recall for 2007 to 2011 in the near future for an electric vacuum pump retrofit...

[Yom]

That will be like extracting blood from a stone as it is not a safety issue under normal vehicle operation.

You'd better off cutting losses and buying a Penstar or Diesel powered JK if it presents a major issue.

[Breyten]

Reading through this thread I had thought I had it figured out, although still cant see how loss of vacuum ASSIST would stop both legs pushing the pedal at all. Unless you have rubber legs...

To me it sounds more like you are trying to work against the EBLD system. Think of it as two brake pedals on a closed fluid system. Back to learner driver cars with two sets of pedals, if the instructor jumped on the pedal with both feet, you couldnt do anything.
(disclaimer, i was not a learner, just screwing with a mate).

You would need to get into the nitty grits of the EBLD and braking system to figure out the delay between it removing pressure to the brakes and it removing pressure to the back of the pedal.

However it could also be that at full tilt the EBLD locks out manual control?

The extra pressure from an electrical booster would not help if I am thinking right. If I am not, I would love to know how it all works for fluid/pressure delivery.

Food for thought

[Yom]

Originally Posted by Breyten

Reading through this thread I had thought I had it figured out, although still cant see how loss of vacuum ASSIST would stop both legs pushing the pedal at all. Unless you have rubber legs...

To me it sounds more like you are trying to work against the EBLD system. Think of it as two brake pedals on a closed fluid system. Back to learner driver cars with two sets of pedals, if the instructor jumped on the pedal with both feet, you couldnt do anything.
(disclaimer, i was not a learner, just screwing with a mate).

You would need to get into the nitty grits of the EBLD and braking system to figure out the delay between it removing pressure to the brakes and it removing pressure to the back of the pedal.

However it could also be that at full tilt the EBLD locks out manual control?

The extra pressure from an electrical booster would not help if I am thinking right. If I am not, I would love to know how it all works for fluid/pressure delivery.

Food for thought

One leg, unless you're an epic weights trainer at the gym or work in a physical slave labour type job/trade, is not sufficient to supply enough pressure to the brake pedal when you've lost all power assistance. Two legs I think it would be possible.

I reckon all the people who've had this happen to them have been busy with one leg busy on the clutch pedal. That's how it happened to me! Made a rookie mistake and hit the clutch in a response to a STOP command.

Simple solution to this "problem" is to change your driving style and do not touch the clutch on hill climbs.

[SeaComms]

Originally Posted by Yom

Simple solution to this "problem" is to change your driving style and do not touch the clutch on hill climbs.

Yom Nails it if in a low range gear (like I was) just back off the accelerator a little slower then hit the brakes and if your really quick drop it into 1st at the same time then leave the clutch out.

Still, I would consider it a pretty poor design flaw! Maybe the Pentastar has a smaller manifold and develops less vacuum hence needs the assistance every now and then?

But on the other hand, I was involved in a recovery the other weekend and my Jeep was tied to the one in front that was one of four winching out a JKU. At first I had the engine off in low range first with the handbrake on. After I started moving I jammed the brakes on, and with both feet as hard as I could and was told my wheels were still turning. Had to start the motor to use the vac assist to stop them. BTW, we eventually got the JKU upright and out of the 3 to 4 metre deep hole it was sitting in upside down....

[dan84]

Originally Posted by SeaComms

Yom Nails it if in a low range gear (like I was) just back off the accelerator a little slower then hit the brakes and if your really quick drop it into 1st at the same time then leave the clutch out.

Still, I would consider it a pretty poor design flaw! Maybe the Pentastar has a smaller manifold and develops less vacuum hence needs the assistance every now and then?

But on the other hand, I was involved in a recovery the other weekend and my Jeep was tied to the one in front that was one of four winching out a JKU. At first I had the engine off in low range first with the handbrake on. After I started moving I jammed the brakes on, and with both feet as hard as I could and was told my wheels were still turning. Had to start the motor to use the vac assist to stop them. BTW, we eventually got the JKU upright and out of the 3 to 4 metre deep hole it was sitting in upside down....

Any pics of that recovery SeaComms?