How to use the retarder in the 1988 FC

[seanbirm01]

What is the proper use of the retarder in the 1988 FC. Should I drive with it on or off? What exactly does the lever on the left side of the steering column do? Does the lever adjust the retarding level or what? A quick lesson will be appreciated. Thanks

[Frank W.]

Hopefully an '88 FC owner will pipe up soon. But if your on your maiden trip -- master switch on dash can be left on (basically system on/off) and the control lever switch FORWARD for normal driving, moved AFT for retarding force.

On an '85 FC with Allison transmission: The Jacobs Retarder is an electric/magnetic device that when activated creates "drag" via magnetic resistance. No involvement with transmission or exhaust (such as an exhaust brake). There is a switch on dash for system on/off AND a lever switch near transmission that in the forward position is "off" and each position moving aft turns on higher levels of retarding force. Primary use is coming down grades/hills/mountains where you use the retarder, transmission and brakes to moderate speed as dictated by need.

Key operating points are to ensure the lever control switch is off/forward when you want system OFF, and back aft when you want slowing effect. The effect is noticeable at full retard - like very light braking. The unit itself looks like a extra differential mid drive shaft. There is one grease point and DO NOT neglect to grease it - mine takes about 10-20+ pumps.

[Steelwheels]

Originally Posted by seanbirm01

What is the proper use of the retarder in the 1988 FC. Should I drive with it on or off? What exactly does the lever on the left side of the steering column do? Does the lever adjust the retarding level or what? A quick lesson will be appreciated. Thanks

I'm still learning myself, but yes I would say drive with it on it applies force when you use your brakes. By moving the lever down and forward you increase the braking force applied. If you want to stop hard lay on the force not so fast lay off. As far as I know the only thing you have to watch when using the retarder is your transmission temperature, cool transmission equals cool head.
May the force be with you.
Tell us about your new bird.

[birds_first]

The retarder on the 87-89FC & 89 -92SP is an internal retarder of the ZF transmission. It can be in the on position all the time. While in the on position the retarder is engaged when the brake pedal is applied. Also in the on position the side lever is used when you do not want the mechanical brakes to activate, such as descending a long hill. You can also use the lever in slower traffic situations where you don’t want to keep tapping the mechanical brakes. Whenever using the retarder it is important to watch the transmission temperature gauge, keeping it in the Yellow range is important, exceeding yellow and diving into the Red can be critical to the transmission if in the red for a prolonged period could cause damage. Learning to feather the retarder to keep below red takes practice I have descended some pretty long grades without much use of the mechanical brakes. Learning to use the retarder, along with proper gear selection & maintaining lower speeds from the top of the hill takes time to learn but it can be done. It does take practice. The ZF retarder does slow the coach but it does not operate like the electromechanical retarder on the coaches with the Allison transmissions. The ZF retarder is fluid driven. Use the site Google search feature at the top of this page to learn more on the ZF transmission there are several threads on the ZF and the ZF retarder use.

[seanbirm01]

Correct me if I misstate anything:

1) Leaving the retarder switch in the 'On' position during normal operation is ok.
2) The retarder lever is in an 'Off' position when pushed fully forward.
3) The retarder switch in the 'On' position with the retarder lever in the 'Off' position will light up the retarder light when brakes are applied but no actual retarding is taking place because of the position of the retarder lever.
4) The level of retarding is increased as the lever is pulled back.
5) The retarder lever can be left in one of the 'on' positions to consistently retard the transmission at the same level whenever the foot brake is applied.
6) The retarder lever can be feathered in lieu of using the foot brake to slow the bus

John McG. - I'll head to the ZF threads to get more info

Kiki - I picked up a 1988 FCRB last week from Somerset, KY and drove it home to Chandler, AZ. It's got about 130K on it. New hardwood flooring, new 8.0 diesel generator, new shocks, new alternator, new ac compressor, 3 year old tires all around, 3 year old batteries all around, all the hoses and belts replaced in the past 3 years, new water tank valves, many gaskets replaced throughout the engine and other systems, and good maintenance records in the blue box. I'm the third owner. The first owner had it for about 18 years. The second owner did most of the recent work. He stored it in a climate controlled garage for the duration of his ownership and spent a small fortune replacing and maintaining items that weren't necessarily going bad but he wanted replacing for piece of mind. He hated to let it go but wasn't using his bird due to health issues.


Pictures follow...

[curtsprenger]

Originally Posted by seanbirm01

Correct me if I misstate anything:

1) Leaving the retarder switch in the 'On' position during normal operation is ok.
2) The retarder lever is in an 'Off' position when pushed fully forward.
3) The retarder switch in the 'On' position with the retarder lever in the 'Off' position will light up the retarder light when brakes are applied but no actual retarding is taking place because of the position of the retarder lever.
4) The level of retarding is increased as the lever is pulled back.
5) The retarder lever can be left in one of the 'on' positions to consistently retard the transmission at the same level whenever the foot brake is applied.
6) The retarder lever can be feathered in lieu of using the foot brake to slow the bus

John McG. - I'll head to the ZF threads to get more info

Kiki - I picked up a 1988 FCRB last week from Somerset, KY and drove it home to Chandler, AZ. It's got about 130K on it. New hardwood flooring, new 8.0 diesel generator, new shocks, new alternator, new ac compressor, 3 year old tires all around, 3 year old batteries all around, all the hoses and belts replaced in the past 3 years, new water tank valves, many gaskets replaced throughout the engine and other systems, and good maintenance records in the blue box. I'm the third owner. The first owner had it for about 18 years. The second owner did most of the recent work. He stored it in a climate controlled garage for the duration of his ownership and spent a small fortune replacing and maintaining items that weren't necessarily going bad but he wanted replacing for piece of mind. He hated to let it go but wasn't using his bird due to health issues.

I pulled the trigger at $25,000.

Pictures follow...

Congratulations! To keep my 'Bird database as accurate as possible...can I ask who was the previous owner? Thank you.

[seanbirm01]

Previous owner was Darrell Hicks.

[birds_first]

Sean, The retarder ‘on’ switch is the black rocker switch on the left side panel; it has a small green indicator light. The retarder lever is the lever on the left side of the steering column under the dash; sort of close to your left knee. When the rocker switch (retarder power switch) is on, your retarder will function either by applying your foot brake or by pulling the retarder lever toward you. The green light will get brighter when the retarder is activated. Also think of the retarder lever as if it were your foot brake pedal, to apply brakes you're applying pressure. If your retarder lever is toward you that means it is applied; in the up or horizontal position the retarder lever it is on. You're welcome to call me, but remember I am on the Eastern Time Zone.

[birds_first]

Originally Posted by seanbirm01

Correct me if I misstate anything:

1) Leaving the retarder switch in the 'On' position during normal operation is ok.
2) The retarder lever is in an 'Off' position when pushed fully forward.
3) The retarder switch in the 'On' position with the retarder lever in the 'Off' position will light up the retarder light when brakes are applied but no actual retarding is taking place because of the position of the retarder lever.
4) The level of retarding is increased as the lever is pulled back.
5) The retarder lever can be left in one of the 'on' positions to consistently retard the transmission at the same level whenever the foot brake is applied.
6) The retarder lever can be feathered in lieu of using the foot brake to slow the bus

John McG. - I'll head to the ZF threads to get more info

.

I think #5 may be an incorrect statement, with the rocker switch (power switch) on your retarder is functioning with the lever engaged in any position regardless of the use of the floor brake pedal.... With the rocker switch on the retarder will engage either with the foot brake or the lever; with the use of the lever only you have no mechanical brakes at the brake drums, if that make sence, but you are braking through the transmission.

[seanbirm01]

So if I am foot braking with the retarder lever in the full forward position and the rocker switch in the on position - is the retarder actually functioning or does the lever.need to be pulled back some for the retarder to engage?