# Hard Brake Pedal @ Low Engine Vacuum on 2003 2500HD???



## BigRedBarn (Jan 4, 2003)

I thought this topic was discussed somewhere here once before, but my feeble attempt at a search came up empty.  I apologize if this topic's been discussed here before.

I had this happen to me a couple times before during normal driving and I just thought it was a fluke. I would be accelerating and then stomp on the brakes and get a hard brake pedal which would then slowly go down and give me brakes (2003 2500HD regular cab 8100 w/ Allison 5-speed automatic).

But, it happened again the other day when I buried one of my old tractors out back but good. My old Ford N Series tractors haven't any live hydraulics or PTO, so when 3-point finishing mower blades got into the clay-muck we call dirt around here, I couldn't get the hydraulics to lift the mower (because the blades were in the muck and wouldn't spin, the hydraulic pump wouldn't spin either) and so the tractor couldn't get itself out of the muck.

So, someone drove my truck in the high and dry areas to pick me up so I could go get tractor #2 to get tractor #1 unstuck. Going downhill for this person picking me up was no problem. Then I tried to go back up (slight grade, really) very slowly and not risking turning around, either, very carefully. Yet, try as I might not to, I still buried my truck.

So (this is a great story, really, so please don't get bored just yet) I called my cousin who came over. He right away said "You got that truck stuck? No way. I'll hop in and get it out." Yeah, right, famous last words. He just put it in deeper into the clay. The clay-dirt we have here in Western NY (officially called "Cheektowaga Red Clay" I think after one of our towns here) gets into the tire lugs and you might as well have slicks on a truck or tractor because the clay fills in the tires perfectly. So, he takes his mid-90's Dodge ¾-ton 4X4 and hooks up to my truck. He gets stuck. He unhooks the chain, and his Dodge is still going nowhere and is in just as deep as my truck.

So, we walk the long walk back to the barn to get tractor #2 out and yank repeatedly on my truck to get it unstuck. After all, 120 in³ of 6.1:1 compression-ratio 60-year-old flathead I4 engine rated at 23 HP at the drawbar doesn't have a lot of grunt to get a 6000++ pound truck out of the muck. But, we eventually did it (and broke an original Ford front bumper costing more than $100 in the process).

However, my cousin kept asking me why I wasn't putting the brakes on when he tugged so I was a bit out of the hole the next time he tugged. "I couldn't," I told him, "as the brake pedal was hard as a rock" whenever I stomped on the brake pedal after gunning the engine to spin the tires. The pedal was hard as a rock every attempt we made. Eventually, the brake pedal would go down while sorta making a funny wheezing noise (from under the hood I think).

Anywho, long story short, we got my truck, his truck and tractor #1 unstuck using tractor #2. It's amazing what those old tractors can do. But, with lots of gear reduction, tall tires with big lugs and not worrying about beating the snot out of them, tractor #2 got all 3 unstuck. Neighbors watching were betting we'd have to call AAA. They scoffed at the notion that one of my 60 year-old little underpowered Ford N Series tractors could get either of those trucks (really buried deep, I might add) out of that clay-muck while nearly getting stuck in the process. By the way, the fields are a bit torn up as I look out my office window right now. Oh well, another job to add to the list... get a load of topsoil and go around and fill in the ruts and seed the dirt. Fun??? Wow!!!

*But, getting back to my concern, is this a common problem on the 2003 Silverado's, that is, lack of vacuum brake assist after accelerating during a panic stop? Is there any service bulletin on this that anyone knows of? Or, do you thing I might have an isolated problem? *

I did look under the hood for a vacuum leak and found nothing. My concern is that I'm going to want to make a panic stop someday and have a rock-hard brake pedal and delayed braking while waiting for the vacuum to catch up and give me assist.

By the way, I drive using only my right foot. I don't brake with my left foot, so there is a slight delay between when I let off of the gas and apply the brakes. That's the way I was taught to drive an automatic (and I always reserve my left foot for when I have a clutch to push, I guess).

I appreciate any opinions or info. Thanks in advance.

"Oh... you got _that_ truck stuck? In this little bit of mud? Oh yeah, I'll get that unstuck, no problem." Ha!!!


----------



## ratlover (May 5, 2003)

my 03 duramax dont do it but it is a different animal. time to take her to the dealer IMO dont sound safe.


----------



## calhoun (Oct 18, 2003)

I doidn't think they had vaccuum assist. Arn't they all hydro boost off the power steering pump??


----------



## crashz (Jan 12, 2004)

That big 8.1L should easily make a ton of vacuum.With a stock intake, you should be pulling vacuum even at WOT. Sounds like you have a big leak. Time for a dealer visit


----------



## BigRedBarn (Jan 4, 2003)

Thanks for the opinions.

I'll take it in to the dealer when I get the time (unlikely as the warm weather has me even busier than usual). I'll have to make it a priority. 

I'll try to remember to post a follow-up.


----------

