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09-23-2017, 08:23 AM
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#1
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Senior Member
Join Date: Apr 2015
Posts: 349
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Excessive brake pedal pressure
I haven't noticed this subject being discussed, so I'll broach it now.
The pedal pressure required to get my '06 Alpine 40 stopped seems to be way too much. I say this from the viewpoint of a man 6'1", 240 lbs. The coach only had 15,000 miles on it when we bought it, and has about 28,000 on it now. The brake pads are virtually unworn. Last year, after seeing discussions about master cylinders, I got one with the slightly smaller bore and had it installed. It seemed to improve the braking slightly, but not as much as I had hoped. I use the engine brake on max at all times. I'm wondering if the power assist booster is not working as it should, and is there some way to check the pressure? I feel that the hydraulic pump on the engine is working OK, because the power steering works fine. I'm in a quandary as to how to proceed to solve this problem. Does anyone else feel like this is a problem?
Dudley Do-Right, '06 Alpine 40 MDTS
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09-23-2017, 08:45 AM
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#2
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Senior Member
Join Date: Dec 2016
Location: So Cal
Posts: 1,368
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When was the last time you adjusted your brake chamber slack adjusters?
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09-23-2017, 09:06 AM
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#3
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Senior Member
Alpine Owners Club
Join Date: Apr 2007
Location: Concrete, WA
Posts: 842
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Quote:
Originally Posted by 1doodadd
When was the last time you adjusted your brake chamber slack adjusters?
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Probably never because these are hydraulic brakes.
__________________
Janet and Todd Legg
2018 Tiffin Allegro Bus 40SP
Previous RV-2006 Alpine Apex M-40FDQS
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09-23-2017, 01:16 PM
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#4
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Registered User
Join Date: Oct 2016
Posts: 3,026
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Dudley,
I believe the master cylinder upgrade involved a larger cylinder not a smaller one. It is interesting that you state the brakes felt better after replacing the cylinder and now after a year they feel less responsive to pedal input. A couple of causes could be air in the lines or improperly adjusted calipers. If the brake shop that installed the cylinder is conveniently located they might be willing to bleed the system and test the brakes to determine where the problem may be. If your handy or have a handy friend you could do the work yourselves.
A final thought, did another driver or a curious grandchild adjust the pedals from your normal driving position?
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09-23-2017, 04:27 PM
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#5
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Senior Member
Join Date: Nov 2005
Posts: 7,383
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Actually--it is a smaller piston bore in the "upgrade" M/C which translates in to more mechanical advantage. "Assume" they performed a wheels-off brake fluid flush when they changed out the MC. If not, do you know when the fluid was changed/flushed? Your thoughts on the power boost could be an issue but don't recall any recent threads on this forum. I don't have the adjustable pedals on my 2003 but have helped 4-5 other owners swap-out M/C on their rigs over the years--they observed about a 30% improvement [their words] in required pedal pressure with little or no increase in pedal travel. Are you sure the upgraded M/C was a 3/4 inch bore????
PS-- Several owners have had the pivot shaft on the outside bulkhead cut and re-welded to increase mechanical advantage. Sure would want an "experienced" welder working on that project....
__________________
Old Scout
2015 IH45 Foretravel
2003 Alpine 40' MDTS [Sold]
New Braunfels, Texas
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09-23-2017, 05:19 PM
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#6
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Senior Member
Join Date: Jun 2011
Location: FL
Posts: 11,385
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I had a Workhorse chassis that took two feet to stop the darn thing. They did some work on it to improve it but it was never good.
If I had kept it I was going to change the brake lines across the rear axle. They were smaller that the one that fed them so I think it was reducing my pressure advantage. I think it could have been improved greatly.
__________________
Certified Senior Electronic Technician, Telecommunications Engineer, Telecommunications repair Service Center Owner, Original owner HR 2008
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09-23-2017, 05:58 PM
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#7
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Senior Member
Join Date: Nov 2005
Posts: 7,383
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OOPS--bad math skills and poor memory--believe OEM MC bore was 2" and the upgrade is 1.5" -- so in theory, an approx. 25-30% improvement in pedal pressure might be expected. Several owners have also replace the rubber brake hoses in the wheel-wells with steel-braided hoses, believing the potential for rubber hoses to expand could reduce pressure to calipers??????? Ref previous post, not sure how you would/could adjust the calipers/pistons on our Alpines?????
__________________
Old Scout
2015 IH45 Foretravel
2003 Alpine 40' MDTS [Sold]
New Braunfels, Texas
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09-23-2017, 07:39 PM
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#8
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Senior Member
Join Date: Oct 2014
Posts: 7,867
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Yup, hydraulic disk brakes by definition are "self adjusting".
But they do require maintenance:
Brake fluid changes.
On sliding caliper (earlier Alpine models) the slides need to be cleaned and lubed with a caliper slide grease. Frequency depends on how often the coach is uses (the more frequent, the less maintenance requires) and whether there are other "corrosion" contributors such as driving with salt on the road, parking at the sea shore, etc.
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
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09-23-2017, 07:49 PM
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#9
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Senior Member
Alpine Owners Club
Join Date: Jun 2007
Location: Lake Wales, FL
Posts: 3,113
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Quote:
Originally Posted by Dudley do-right
I haven't noticed this subject being discussed, so I'll broach it now.
The pedal pressure required to get my '06 Alpine 40 stopped seems to be way too much. I say this from the viewpoint of a man 6'1", 240 lbs. The coach only had 15,000 miles on it when we bought it, and has about 28,000 on it now. The brake pads are virtually unworn. Last year, after seeing discussions about master cylinders, I got one with the slightly smaller bore and had it installed. It seemed to improve the braking slightly, but not as much as I had hoped. I use the engine brake on max at all times. I'm wondering if the power assist booster is not working as it should, and is there some way to check the pressure? I feel that the hydraulic pump on the engine is working OK, because the power steering works fine. I'm in a quandary as to how to proceed to solve this problem. Does anyone else feel like this is a problem?
Dudley Do-Right, '06 Alpine 40 MDTS
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Over the years being on this forum I have seen multiple postings on brake pedal pressure. I think what we are seeing is a second or third round of these questions being asked by next generation owners. Dudley I respectfully suggest you do a search of the forum to find those prior postings, this will avoid what I call "the IIRC syndrome", some of us old folks don't recall things so well and we try to remember correctly in an effort to assist, (I know I have done it more than once). This forum has a rich history and if the search function is used you can get answers for questions almost immediately, no need to wait for someone to respond, a large number of issues have already been addressed by both present and former owners. This is not meant to demean anything posted, but rather to assist the new generation of owners in using this forum and get a rapid response to their issues. Please take these comments as a helpful reminder many, if not all, of the issues have been previously discussed by Alpine owners and postings from owners of some other brand that do not know how an Alpine coach was made will not lead you astray.
__________________
Dave, Bobbi and Fenway
2005 38' FDTS Alpine Limited, 2016 Jeep Grand Cherokee Limited
Lake Wales, FL
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09-24-2017, 08:56 AM
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#10
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Registered User
Join Date: Oct 2016
Posts: 3,026
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Thanks Old Scout. It's been over a year since I did my pre purchase due diligence and since the PO had the MC upgrade installed the specifics have been moved to deep storage. My "man brain" instinctively went to the "more displacement equals more power" school of thought.
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09-24-2017, 12:19 PM
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#11
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Senior Member
Alpine Owners Club
Join Date: May 2008
Location: Ocala, FL
Posts: 260
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Try moving the adjustable brake pedal all the way out toward the seat.
You should notice a difference between all the way out and all the way in.
__________________
Jim & Sandy
2008 34' FDDS Alpine
Limited SE
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09-26-2017, 06:37 AM
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#12
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Senior Member
Join Date: Feb 2015
Location: KY
Posts: 250
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Your right Dave there's aworld of info in the past post and I believe I was lucky to come aboard with my 2003 Coach and have Old Scout ,Brett, Dave and others to jump right in and help me out. Here's the thing as my wife would say you go into it to deep. Just talking if the pads has oil on them it would be hard to stop, if the pads had been over heated ,it would be hard to stop with a hard pedal. But if the hose was soft it seems like it would be hard to stop but soft pedal also. if the booster pump was weak it seem to me it would be softer, I see if you had dirt and not changed oil it would be hard but soft also. So my point is when someone says its hard to stop what area does it cover. I agree about the history I go back all the time. Thanks
Larry and Tammy
2003 38Fd Alpine 350 Cummins
2007 Jeep Wrangler Unlimited
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09-26-2017, 07:00 AM
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#13
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Senior Member
Join Date: Nov 2005
Posts: 7,383
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Good summary Larry--the only other issue with the Alpine braking system is the impact, or lack of impact, of the ABS system on braking. Have been lead to believe that the brake system would simply by-pass a non-functioning ABS--don't know if that is true or not. The ABS is the one "wild-card" in my understanding of this issue....
__________________
Old Scout
2015 IH45 Foretravel
2003 Alpine 40' MDTS [Sold]
New Braunfels, Texas
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09-26-2017, 07:17 AM
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#14
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Senior Member
Join Date: Jul 2014
Posts: 35,317
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They make more aggressive brake pads for heavy trucks.
For a little work and a few bucks, you could try a more aggressive set of pads.
They may wear faster but if it helps in stopping, it may be worth it.
Here is a site I found.
https://www.powerstop.com/product/power-stop-z36/
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