Hello,
Just purchased a 1967 122 Estate wagon. Had a 122s sedan back in the 7o's so have some old knowledge but have a few questions.
Somewhere along the line this care was updated w/ 2.0 motor w/ twin SU's & has an electric fuel pump instead of mechanical. Need to know advantages or disadvantages to either?
Car has a high idle?
Brakes are very weak?
Car is very solid...
Any assistance & advise is welcomed...
Newbee w 1967 122 estate
Advantages:
Noisy. You can here it when you turn the key on so you know it is pumping.
Immediate pressure. If the car sits for long periods of time, the float bowls will fill when the key is turned ON. With a mechanical pump, it takes several seconds of cranking to fill the bowls.
Disadvantages:
Noisy. You can hear it whenever the car is not moving. But, Amazons are noisy anyway. It just becomes another diagnostic clue when something isn't right.
May need a pressure regulator. The SU float inlet needles are very sensitive to excess pressure. More than 2-3 psi is too much and will force the needle off the seat. Flooding ensues.
Electrical. A mechanical pump seldom fails and can be rebuilt when it does. An electric pump will eventually wear out. It might not happen for many thousands of miles but it will quit eventually. I would not consider this a major problem. Just have a spare ready to swap out.
High idle:
Possible vacuum leak. Most probable on high mileage carbs is pulling air around the throttle shafts. The shafts will need rebushing if this is the case. Other sources of vacuum leaks can cause high idle too, so don't overlook basic things like the gaskets and hoses.
On my car, someone had reassembled the carbs incorrectly after a botched rebuild attempt. They had installed the rear jet on the front carb and vise versa. The choke linkages were bent in an attempt to make the misplaced jets work as installed. The throttle plates would be held open and the jets would remain down just a little bit after the choke was shut-off. It took awhile to find the problem because I was not familiar with SU carbs. It was resolved when I sent the carbs off for new throttle shaft bushings and jets. When I saw how it was supposed to go together, the problem was obvious.
The most common problem with weak brakes is excessive mechanical motion in the rear brakes. If the brake pedal travel is excessive but presents a firm pedal near the bottom of the travel, this is a possible reason.
On the front disks, the pistons move back only as far as the disk pushes them back. Shoe brakes have a lot more slack in the system. The major problem is the slave cylinder pistons will move back in the bore. That means the piston has to move some distance back to where it can start doing work when the line is pressurized.
Assuming there is no air in the system, and the shoes are good, the best fix is to add a 10 lb. residual pressure valve to the rear brake circuit. The place to put it is at the input to the brass 3-way junction block on top of the rear axle. The residual valve will keep the slave pistons from retracting back into their bores.
--sd
Noisy. You can here it when you turn the key on so you know it is pumping.
Immediate pressure. If the car sits for long periods of time, the float bowls will fill when the key is turned ON. With a mechanical pump, it takes several seconds of cranking to fill the bowls.
Disadvantages:
Noisy. You can hear it whenever the car is not moving. But, Amazons are noisy anyway. It just becomes another diagnostic clue when something isn't right.
May need a pressure regulator. The SU float inlet needles are very sensitive to excess pressure. More than 2-3 psi is too much and will force the needle off the seat. Flooding ensues.
Electrical. A mechanical pump seldom fails and can be rebuilt when it does. An electric pump will eventually wear out. It might not happen for many thousands of miles but it will quit eventually. I would not consider this a major problem. Just have a spare ready to swap out.
High idle:
Possible vacuum leak. Most probable on high mileage carbs is pulling air around the throttle shafts. The shafts will need rebushing if this is the case. Other sources of vacuum leaks can cause high idle too, so don't overlook basic things like the gaskets and hoses.
On my car, someone had reassembled the carbs incorrectly after a botched rebuild attempt. They had installed the rear jet on the front carb and vise versa. The choke linkages were bent in an attempt to make the misplaced jets work as installed. The throttle plates would be held open and the jets would remain down just a little bit after the choke was shut-off. It took awhile to find the problem because I was not familiar with SU carbs. It was resolved when I sent the carbs off for new throttle shaft bushings and jets. When I saw how it was supposed to go together, the problem was obvious.
The most common problem with weak brakes is excessive mechanical motion in the rear brakes. If the brake pedal travel is excessive but presents a firm pedal near the bottom of the travel, this is a possible reason.
On the front disks, the pistons move back only as far as the disk pushes them back. Shoe brakes have a lot more slack in the system. The major problem is the slave cylinder pistons will move back in the bore. That means the piston has to move some distance back to where it can start doing work when the line is pressurized.
Assuming there is no air in the system, and the shoes are good, the best fix is to add a 10 lb. residual pressure valve to the rear brake circuit. The place to put it is at the input to the brass 3-way junction block on top of the rear axle. The residual valve will keep the slave pistons from retracting back into their bores.
--sd
--
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 59 year old fat man.
Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 59 year old fat man.
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