2 (Page 2 of 2)  

"B" - is for "Brakes"- By Ian Hopley (Page 2)

This brings me neatly to the topic of bleeding the brakes. This shouldn't be any different to any other car but it is worth noting that the workshop manual advises bleeding both the callipers on any one side simultaneously. The 164 has a diagonally split braking system, so bleeding (say) the right hand front and the right hand rear wheels at the same time should allow fluid out of both circuits at the same time. Obviously, this makes it a three-person job but at least its not one you would expect to undertake frequently. The manual also warns that there MUST be load on the rear axle when bleeding the brakes. This is because the rear brake pressure proportioning valve won't allow fluid through to the rear wheels if there is no weight on them. The pressure proportioning valve is a device to vary the rear brake pressure as the weight on the rear tyres increases. These are common on many cars. Without it, the rear wheels would either lock prematurely under heavy braking (vary dangerous!) or they wouldn't do enough work when the car was heavily laden. The only thing I've never been able to understand is why on earth a car with ABS was fitted with one - unless it was just as a "fail-safe" in case the ABS packed up! The valve on the 164 is located in a bracket near the middle of the rear crossmember. It has four brake pipes screwed into it and its plunger engages in a linkage which effectively slides the valve piston in and out as the suspension goes up and down. It is not possible to service these valves so all you can reasonably do as a DIY proposition is make sure that the piston is free to slide in and out. If it doesn't, the whole valve needs replacing.

If you do have the misfortune to have to undo the unions on the brake pipes into the valve (or any of the unions under the car or wheelarch), there is a good chance they will be corroded and/or seized. Again, this is not a problem peculiar to elderly 164s but one of the joys of maintaining almost any car more than 10 years old. One helpful tip that really does seem to work is to liberally coat the union and the pipe where it enters the union with old grease. Put a really good blob on so that you almost can't see the union or the first half inch of pipe entering it. Provided this protective layer of grease isn't breached by water, the union shouldn't corrode and seize. This will save HOURS in years to come! One cautionary note here is to be very careful with the flexible rubber brake hoses at each corner of the car. Some greases will attack certain types of rubber. I have no idea what sort of rubber the 164 hoses are made of and this wouldn't be the best way to find out!

The master cylinder is located on the end of the servo on the passenger side of the car - under the cooling system header tank. The force applied to the pedal is taken across the car by a huge rod running across the bulkhead behind the lower part of the dashboard. Neither the master cylinder nor the servo unit are known to be particularly troublesome. In any case, they are completely conventional items and no different to most other cars in their operation. One item worth mentioning is that the brake fluid reservoir also feeds the clutch on cars with a hydraulic clutch. This means that a loss of brake fluid could be as a result of a clutch master or slave cylinder problem rather than anything to do with the brakes. On the V6, the slave cylinder is on top of the clutch bellhousing and is very easy to access. The same cannot be said for the master cylinder which is on the driver's side sandwiched between the bulkhead and the back of the engine. Of course, if you do start loosing brake fluid, there is a float switch on top of the reservoir which illuminates the warning light on the dashboard. On early cars, this was a crude affair consisting of a washer which was pressed against two contacts by the buoyancy of the float. Electrical contact needed to be made to keep the light off. As the cars aged and the contacts became dirty, false activation of the lamp could be achieved. This is very easy to fix. Prise off the rubber "push-to-test" cap from the reservoir lid and if you have one of the older switches, you will see the washer and contacts. If you have a later car, you won't see anything because these had a more sophisticated arrangement whereby a magnet on the top of the float pulled the contacts of a reed switch together. These are encased in glass and really cannot be repaired.

 

Returning to the old type, carefully clean the washer and contacts with switch cleaner (available in spray cans from Maplins or RS. Don't abrade the contacts. This will work for a short time but as it also removes the plating, they will corrode even faster next time! Finally, before leaving this subject, it is worth mentioning that all the level switches on early cars worked the same way - screen wash fluid and coolant so if you get false alarms from these, it's worth a quick look. Lastly, a few tightening torques from the manual might be useful:

Item Lb Ft Nm

Item Lb Ft Nm
Wheel bolts 70 - 77 95 - 105
Front calliper to upright 38 - 43 52 - 58
Setscrew holding front calliper sliders 23 - 28 33 - 38
Rear calliper to upright 33 - 36 44 - 49
Setscrew holding rear calliper sliders 23 - 26 31 - 35

Other useful data:

Fluid capacity (complete system with ABS): 0.8 litres.

Fluid capacity (complete system without ABS): 0.6 litres.

Brake fluid type: DOT 4

Front pads: Pad with wear indicator goes on the INSIDE

Top   Previous Page

Article Content and Photos by Ian Hopley.
© Ian Hopley / alfisti.co.uk 2002

Alfisti.co.uk provides this information in good faith, but does not assume any responsibility or legal liability whatsoever, for the accuracy, usefulness or completeness of any of the information.