ABS question for 760 rear axle swap

[mccanlessdesign]

I will be removing and replaciing the rear axle in my 1889 760 wagon
(solid axle) with an older GM axle to handle more torque.

Questions:
1) How will this affect the front ABS? The new rear axle has discs,
but no provisions (or plans) for ABS. Are there rotation sensors on
the stock axle that will confuse the ABS brain by their absence? Can
I just connect the brake lines and have ABS on the front only ?

2) How about correct front to rear brake proportioning? Would I need
to add an adjustable proportioning valve, or is the fact that I still
have four-wheel discs mean that the factory split is still mostly
correct?

3) Where is the electronic speedo pickup? I assume it's a little
chopper wheel in the axle housing somewhere. The new drivetrain has a
GM cable-driven speedo drive, so I need to convert that to an electric
signal to feed to the stock Volvo speedo.

4) I understand there is a specific capacitor on the Volvo tach one
changes to correctly read a V-8 rather than the four. Anyone have any
ideas on that?

Thanks - Forrest

 

[Mike F]

I will be removing and replaciing the rear axle in my 1889 760 wagon
(solid axle) with an older GM axle to handle more torque.

Questions:
1) How will this affect the front ABS? The new rear axle has discs,
but no provisions (or plans) for ABS. Are there rotation sensors on
the stock axle that will confuse the ABS brain by their absence? Can
I just connect the brake lines and have ABS on the front only ?

2) How about correct front to rear brake proportioning? Would I need
to add an adjustable proportioning valve, or is the fact that I still
have four-wheel discs mean that the factory split is still mostly
correct?

3) Where is the electronic speedo pickup? I assume it's a little
chopper wheel in the axle housing somewhere. The new drivetrain has a
GM cable-driven speedo drive, so I need to convert that to an electric
signal to feed to the stock Volvo speedo.

4) I understand there is a specific capacitor on the Volvo tach one
changes to correctly read a V-8 rather than the four. Anyone have any
ideas on that?

Thanks - Forrest

1) and 3) The front ABS will not work. The ABS is a system that has to
all be there for any of it to work. The speedo and ABS share a sensor
that is mounted in the diff cover. There is a pickup wheel on the
carrier.

2) That depends on the relative efficiency of the new brakes vs. the
Volvo brakes, compounded by the extra weight your going to have on the
front end.

 

[mccanlessdesign]

Allright, does that mean I should try to mount the sensor on my new
axle? It's actually a '75 Eldorado FWD setup used in the rear, but
all the components are pretty standard GM. My weight distribution
will be less on the front than stock, more on the rear - 8.2 liters
worth. BTW, my ABS light has never come on, but my speedo/odo comes
and goes, so I guess the wire downstream from the split to the ABS is
faulty. Thanks for the input

 

[Mike F]

Allright, does that mean I should try to mount the sensor on my new
axle? It's actually a '75 Eldorado FWD setup used in the rear, but
all the components are pretty standard GM. My weight distribution
will be less on the front than stock, more on the rear - 8.2 liters
worth. BTW, my ABS light has never come on, but my speedo/odo comes
and goes, so I guess the wire downstream from the split to the ABS is
faulty. Thanks for the input

There needs to be a gear or other type of device with a specified number
of teeth that the pickup has to be located close to to work. It'll be
obvious what you need to do if you remove the cover on your old
differential.