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56Clippers

Re: Mojave Tan - A 1956 400 Saga

#241

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Quote:

For checking the vacuum to the brake system I connected to the hose at the tank.

Assuming you removed the connection to the tank and that is where you connected the gauge, your gauge is measuring the engine vacuum minus any connection and booster losses. Being that your vacuum readings are low, I was suggesting that you connect the gauge directly to the vacuum port on the carb. Any difference in readings indicate vacuum leaks in the booster or connections. You should also test the tank for leaks. If the reading from the vacuum port on the carb is low, you need to take a look at the engine.

Posted on: 4/16 19:37

Ross

Re: Mojave Tan - A 1956 400 Saga

#242

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There is no vacuum port available on the Rochester carb itself as that place is taken up by the big brass fitting that holds the check valve and the one line heading off to the wiper distribution manifold. Check your vacuum on that hard line as there is no restriction.

The vacuum port that goes to the vac advance should show essentially zero vacuum when the engine is idling as the carb is designed to shut it off.

I've had several cars in over the years where the idle was turned up enough that the vacuum advance was was activated. When the timing was then set to "spec"it was a VERY false reading as the vac advance was already "all in". That is why I strongly prefer to disconnect that vac advance line while setting the timing. The Rochesters are somewhat prone to this problem if the idle speed is a little high, the Carter 4bbl carbs even more so.

Posted on: 4/16 20:10

56Clippers

Re: Mojave Tan - A 1956 400 Saga

#243

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Quote:

Ross wrote:
There is no vacuum port available on the Rochester carb itself as that place is taken up by the big brass fitting that holds the check valve and the one line heading off to the wiper distribution manifold.

I should have said to connect the gauge to the check valve fitting.
The idea is to measure the vacuum that feeds the brake system independent of the components of the brake system.

Posted on: 4/16 20:55

kevinpackard

Re: Mojave Tan - A 1956 400 Saga

#244

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Thanks Ross and Howard. I did connect the vacuum gauge to the hard line going to the wipers after I tightened everything up. It was the same reading as at the tank. My thought was as you described Howard....check vacuum before all the brake components, then if different there check it at the BTV and at the tank to see where the vacuum leak was.

I'll disconnect and plug the vacuum advance port and recheck timing. My guess is it is going to be quite off when I do that. Hopefully that's it and I'll be able to dial in the timing and vacuum all the way.

I think my idle settings are partly to blame. Manual states 275-400 in neutral, which is really low. I think I'm too high.

Posted on: 4/16 23:06

R H

Re: Mojave Tan - A 1956 400 Saga

#245

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Kevin

One way to till if idle is to high.

When you come to a stop and your in D, it down shits hard. (Converter) cuts out.

Also if you are in H, shift to L, at a stop, car leaps.. idle to high.

The shifts should be gentle.

A tachometer would help you.. I have one hooked up. Off the steering column.

Posted on: 4/17 1:58

Riki

56Clippers

Re: Mojave Tan - A 1956 400 Saga

#246

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Quote:

kevinpackard wrote:
I did connect the vacuum gauge to the hard line going to the wipers after I tightened everything up. It was the same reading as at the tank.

Was the hose to the brakes connected to the check valve at that time?

Posted on: 4/17 14:35

kevinpackard

Re: Mojave Tan - A 1956 400 Saga

#247

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Quote:

56Clippers wrote:
Quote:

kevinpackard wrote:
I did connect the vacuum gauge to the hard line going to the wipers after I tightened everything up. It was the same reading as at the tank.

Was the hose to the brakes connected to the check valve at that time?

Yes, and all the connections on the brake side were secure. Maybe I can check it again, but this time put a cap on the end of the check valve to eliminate the entire brake assembly from the equation.

Riki - When I go from Park to anything else it is a hard shift for sure. I'll mess with it and see if my multimeter gives me an accurate reading on the RPMs. Probably need to adjust it down.

I haven't yet had time to do any checking since Monday. Weekdays are impossible to find any time at all to do work. Full and busy days at work bleed right into full and busy evenings full of kids sports and other obligations. Rinse and repeat.

Posted on: 4/17 17:21

kevinpackard

Re: Mojave Tan - A 1956 400 Saga

#248

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Had a few minutes after work today to recheck everything. Figured out how to get the multimeter to read the RPMs correctly (I think) and set idle in neutral to just under 400.

Disconnected and plugged the vacuum advance line and rechecked timing. It was a couple degrees off, so I brought it back to 10. Checked vacuum at the line to wipers, before the check valve for the brakes. About 15inHg, which is better but not good enough.

After a little more digging, found a leak at the vacuum tank connection. Looks like hose clamp that is on there is the wrong size and is not sealing well enough. Adjusted it and vacuum jumped up to 18 inHg steady.

Brakes are significantly improved. Now a light touch applies the brakes easily, and a medium push really slows it down. Not locking all wheels, but much, much better than before. It feels as I imagine it should.

Click to see original Image in a new window

Posted on: Yesterday 23:29

56Clippers

Re: Mojave Tan - A 1956 400 Saga

#249

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Quote:

kevinpackard wrote:
Checked vacuum at the line to wipers, before the check valve for the brakes. About 15inHg, which is better but not good enough.

After a little more digging, found a leak at the vacuum tank connection. Looks like hose clamp that is on there is the wrong size and is not sealing well enough. Adjusted it and vacuum jumped up to 18 inHg steady.

Brakes are significantly improved. Now a light touch applies the brakes easily, and a medium push really slows it down. Not locking all wheels, but much, much better than before. It feels as I imagine it should.

Maybe a hard push will get the wheels to lock.

Quote:

Maybe I can check it again, but this time put a cap on the end of the check valve to eliminate the entire brake assembly from the equation.

Have you tried this yet?

Here is the equation:

Posted on: Today 5:37

kevinpackard

Re: Mojave Tan - A 1956 400 Saga

#250

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Thanks Bob, I still need to plug the rear off the check valve and see what it's like. I replaced the clamp on the vacuum tank and fixed that leak. Vacuum is staying steady and brakes feel pretty good. They squeal like crazy though. Need to fix that.

Took the 400 out on it's first actual voyage today, to go get burritos between work sessions on my brother in law's car. Not far, only about 10 miles total but it did just fine. Definitely some other things to work through, but I'm now less afraid that it will leave me stranded

Posted on: Today 18:12

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