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Jason952
Active Member
United States
10 Posts |
 Posted - 05/05/2008 : 1:17:08 PM
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| Anyone having trouble with these I have replaced 3 in 1 month because of external fluid leak |
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IBTMech
Top Member
USA
973 Posts |
Posted - 05/05/2008 : 6:30:14 PM
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| Glad I don't have any................ |
If it doesn't fit, FORCE it.
If it breaks, well, it needed replacing anyway.
Pullin' wrenches for 45 years. |
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Trailboss
Senior Member
United States
196 Posts |
Posted - 05/05/2008 : 6:48:05 PM
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| Just curious what is SAHR. I guess I don't have any if I don't know what it is. |
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Bassman
Top Member
USA
558 Posts |
Posted - 05/06/2008 : 03:41:42 AM
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| A SAHR cannister is a "spring applied hydraulic released" cylinder which mounts on the left rear frame rail and applies the driveline park brake via a short cable on IC buses with full power hydraulic brakes. Loosely, it operates like an air brake chamber...the spring applies the brake and hydraulic pressure from the system releases it. It is also tied in to the ABS system and if it is applied in an emergency situation, it brings the bus to a safe controlled stop using the ABS. We had a good bit of problems with SAHR's when they were first released, but following the recall which changed the way they where wired, have been fairly reliable. We have 32 of these buses with only limited problems with the SAHR cannisters. We have never had one leak yet. Our biggest problem with the system is the pumps in the main HCU unit on buses built prior to Sept. 06. The toughest failure for us to work through though is when a pump MOTOR fails in the HCU on one of these earlier units. If it is the front pump motor that quits on a run, there is no pressure supplied to the SAHR and therefore the bus can't be moved. Then, after towing it to the dealer, getting Wabco to cough one of these HCU units up is like pulling teeth. They send the dealer through a bunch of extra steps and lengthy phone call holds to ensure that it really is the HCU unit (they are expensive). The best news is that on these earlier units, Wabco has extended the warranty on the pumps and the HCU units from 3 to 5 years due to some early design glitches. Take some time to play with this brake system on a slippery parking sometime. You will really be amazed at the function of the traction control feature and the anti-lock functions. It is no longer possible to have any fun at all spinning or sliding these units in the snow! They work beautifully. |
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wistech
Active Member
United States
48 Posts |
Posted - 05/06/2008 : 04:07:29 AM
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| Had a few where the big nut on front of SAHR can was loose from the factory where the supply line goes into it. I heard the HCU assembly was $3000 and not available at my dealer yet. Get this...2 Years ago the park brake switch on dash malfunctioned and gave a false signal to SAHR can and applied the park brake at 65 mph loaded with passengers going down highway. The bus couldn't get off highway when it locked up! Makes me long for having a manual cable again. Guess it's o.k. when it works properly. |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 05/06/2008 : 09:36:38 AM
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| Why do they put this crap on busses. I saw one before and it reminded me of the complicated system used on RVs by gm/workhorse P42 chassis. They fail also, usually destroying the drum, shoes and hardware. Cable stretching issuse, missing return springs, you name it. POS from day 1. Do yourself a favor and order air brakes next time. :) |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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Thomasbus24
Administrator
USA
4547 Posts |
Posted - 05/06/2008 : 12:27:51 PM
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quote:
Originally posted by Bassman
It is no longer possible to have any fun at all spinning or sliding these units in the snow! They work beautifully.
Sure it is! Just pull an ABS sensor loose and piss off the computer! Wonder what happens then |
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busgeek++
Advanced Member
United States
253 Posts |
Posted - 05/06/2008 : 6:08:21 PM
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| They just need an ABS/Traction control disable switch! Then when the system is unhelpful/screwing up an attempted maneuver or just not working properly, it can be disabled. |
Buses are not a way of life, they are life |
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dem84skeeprollinup
Top Member
USA
888 Posts |
Posted - 05/07/2008 : 09:55:35 AM
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quote:
Originally posted by Wolf0r
Why do they put this crap on busses. I saw one before and it reminded me of the complicated system used on RVs by gm/workhorse P42 chassis. They fail also, usually destroying the drum, shoes and hardware. Cable stretching issuse, missing return springs, you name it. POS from day 1. Do yourself a favor and order air brakes next time. :)
Doesn't Navistar own Workhorse also? Or is the modek your talking about a pre navistar one? |
Do the world a favor and bring back GMC and Ford conventional chassis......
 
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Edited by - dem84skeeprollinup on 05/07/2008 09:57:39 AM |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 05/07/2008 : 2:16:55 PM
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| 1996 and up. It was called "autopark" |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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wright11
Senior Member
Canada
159 Posts |
Posted - 06/18/2008 : 4:48:04 PM
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| is anyone having problems with the elec. sillynoid on the sahr units, out of 9 units we have replaced 4 so far |
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Bassman
Top Member
USA
558 Posts |
Posted - 06/19/2008 : 03:36:12 AM
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| We have had only limited problems on our 08's. More problems before the recalls were done on the older ones. What year of buses do you have? |
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wistech
Active Member
United States
48 Posts |
Posted - 06/19/2008 : 03:57:12 AM
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| Wright11-- we have replaced about 10 of these already. You are talking about the cut-off coils, correct? They seem to "blossom" from the road salt. |
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wright11
Senior Member
Canada
159 Posts |
Posted - 06/19/2008 : 6:18:06 PM
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| hi all, bass they r 06-07,,yes the coils |
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Topic |
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SAHR
