1970 Ford Bronco 302 - Carburetor, Distributer and Intake Manifold Leaks

[tonytony9]

Hi all,

I am new to the forums and Bronco ownership; I purchased my Bronco recently and am diving into the very overdue maintenance items. I have been working on cars most of my life, although, I definitely consider myself an amateur eager to learn.

Generally speaking, its running and shifting great, although, its leaking from everywhere; oil pan, rear main seal, distributer, carburetor, intake manifold plus a few other areas I am sure I have neglected to mention. I am tackling what I am aware of as immediate first priorities and am looking for advice on where to buy the parts, brands and how-to tutorial threads/videos you would recommend.

1970 Ford Bronco 302 w/ 3 speed manual. Main use case is on-road driving, no off-roading or trail riding.

Carburetor:
It appears to be the stock Autolite 2100 2-barrel carburetor. Since I have to do an intake manifold, worth converting to a 4-barrel? It currently runs great with the stock 2-barrel, does anyone know a reliable rebuild I can buy? Mine is spitting gas out all around the front seal, conveniently near the distributer.

Intake Manifold:
If I am sticking with a rebuilt or replace autolite 2100, anyone have a recommendation for a new manifold? If you all recommend going to a 4, recommendation on an intake manifold to match.

Distributer:
Same as above, recommendation on brands if I stay at 2, recommendation if I go to 4.

Any advice is very much appreciated as I go through this process! Thank you.

 

[EPB72]

Not much time right now but one word of advice rebuild the current carburetor if your planning to stick with the 2bbl ,,, Don't trade that in as a core ever...

 

[661buster1963]

In my experience going to a 4 barrel on otherwise stock engine with have marginal impact on performance. It will however burn a lot more gas. Mine got 18-19, then out 465 Holley on it and got 12-13

 

[661buster1963]

And yes, rebuild the one you have . Most available today are trash

 

[Johnnyb]

Autolite rebuild = super easy and cheap, I used to do them in about half an hour. Autolite is the way to go unless you decide for EFI.

The front and rear seal on the intake manifold are often sources for big oil leaks (like what you see on the distributor), when you install, use a thin coat of gasket seal and make sure they don't move as you lower the intake on.

Valve cover gaskets are also easy, probably the source for a lot of that mess.

I think the distributor has an 0-ring, but unlikely it is leaking from there.

Rear main seal is a bit more difficult, but doable.

Front cover may be leaking too, also just nuts and bolts.

-JB

 

[gnpenning]

The 2100 carb is a great carb. Hopefully none of the screws are stripped causing your fuel leak. Please don't drive it until you get it fixed.

It would be a good idea to check your pcv system and do a compression or cylinder leakage test. Excessive crank case pressure can create oil leaks. Make sure before finding out you have other problems.

The dura spark would be a good distributor change or you can put a ignition module on the points.

 

[m_m70]

Welcome!! You'll get a lot of opinions on this and here's mine. You can go three ways (or more) on this.
1 - spend a couple hundred bucks. - clean motor, rebuild carb and seal things up
2 - spend a thousand + - change to 4 bbl
3 - spend a few thousand + a bit more - EFI conversion
Since you've already mentioned it will see mostly street use AND your happy with the way its running I would go with option 1.
First I think I would clean everything up real good and figure out where your leaks are coming from before changing everything. You may not need intake gaskets and you may not need rear main.

Below are the parts I used and have had good results.

Keep that carb and rebuild it. Do not replace it. Trust us on this. https://www.napaonline.com/en/p/CRB...IIohaMaAiZNEALw_wcB&gclsrc=aw.ds&gad_source=1

Get a set of reusable valve cover gaskets, -https://www.summitracing.com/parts/...C6pKv9uS6poxyD1gNJ3T9Ig95ofqtW9caAitxEALw_wcB

a reusable oil pan gasket, - https://www.summitracing.com/parts/fel-os13260t/make/ford/model/bronco/year/1970

intake manifold gasket set IMPORTANT to get the gasket set wit the steel core! These are the gaskets I went with and have no issues in 8 years. Felpro1250S3
https://www.summitracing.com/parts/...zBxeERCyfkcwMOGAAz54_uiFiDwr4z5YaAuhEEALw_wcB

I would not replace the distributor. I would however put a Pertronix module in it. Just me.....
https://www.amazon.com/dp/B000N2XOHQ/?tag=classicbroncos-20

Check around for best pricing if you go this route. Lots of videos out there for all of this and use this forum as well. It's a great resource and there's great people here happy to help you out!

 

[tonytony9]

Thank you everyone for the advice. I am going to stick with the 2100, either send it out for a rebuild or do it myself. Anyone have any companies they recommend for a rebuild? Need to do more research on the process. Any have additional rec's on a rebuild kit, or is Napa the way to go?

 

[Johnnyb]

Thank you everyone for the advice. I am going to stick with the 2100, either send it out for a rebuild or do it myself. Anyone have any companies they recommend for a rebuild? Need to do more research on the process. Any have additional rec's on a rebuild kit, or is Napa the way to go?

So easy.

1. Four bolts, the fuel line and the throttle - it's out.
2. Piss your wife off by laying paper on the kitchen table, put the carb there.
3. Take the screws out of the horn (top) and it comes off.
4. Pull out the float by hand and needle valve with a small socket.
5. Turn it over and take out 4 screws to remove the power valve cover.
6. Remove power valve with crescent or other wrench.
7. Take it outside and clean with a whole can of carb clean. Let it dry!
8. Get a zip-kit from your favorite parts store.
9. Use the parts in the zip-kit to reassemble. Most importantly, it should have a new power valve.
10. Put the needle valve (should also be new) and float back in.
11. Check float level by sight dry. Needle valve should close and provide resistance.
12. Leave the horn off and re-install carb on vehicle.
13. Get fire extinguisher handy.
14. Crank vehicle until float bowl fills and float stops gas (you can disconnect the coil positive and wrap it with tape to prevent starting and sparks)
15. Gas level should be below lip of bowl by at least 1/4 inch, there might be a spec in the instructions.
16. If level is too high or low, bend the tab at the back of the float to adjust.
17. Once it is right, put the horn on, connect the coil and start it.

Apply common sense when gas is exposed, but too high a fuel level in the bowl will cause flooding. Also, clean all surfaces well and don't use rtv anywhere on the carb.

Good luck.
-John

 

[Johnnyb]

I just reread this and I forgot to add the step about changing the accelerator pump diaphragm, also four screws on the front of the carb.

It's been 20 or so years since I did one!

 

[tonytony9]

I just reread this and I forgot to add the step about changing the accelerator pump diaphragm, also four screws on the front of the carb.

It's been 20 or so years since I did one!

Still very knowledgeable, thank you! I am going to start with just replacing the gaskets for the time being. Car is not bogging or running lean to my knowledge. Goal #1 is to get it back on the road. Although, I agree in the very near future I will set aside for the entire rebuild.

Going to use the kit M_m70 suggested: https://www.napaonline.com/en/p/CRB...IIohaMaAiZNEALw_wcB&gclsrc=aw.ds&gad_source=1

 

[m_m70]

I am going to start with just replacing the gaskets for the time being. Car is not bogging or running lean to my knowledge.

Good idea! If it aint broke..............

 

[tonytony9]

Good idea! If it aint broke..............

I just reread this and I forgot to add the step about changing the accelerator pump diaphragm, also four screws on the front of the carb.

It's been 20 or so years since I did one!

After further inspection, it appears that it is specifically the accelerator pump which is leaking. If your eyes are sharp, look to the right of the red arrow and you will see the gasoline drip. Going to keep the carb attached to the gasket/spacer and try to remove the pump and replace gasket.

 

[Oldtimer]

Accelerator pump covers a notorious for not being flat, and leaking.
Remove cover and flatten with a piece of fine emory cloth on a flat surface (I use table saw top).

 

[tonytony9]

Accelerator pump covers a notorious for not being flat, and leaking.
Remove cover and flatten with a piece of fine emory cloth on a flat surface (I use table saw top).

Makes sense. My carb rebuild kit came with a brand new diaphragm. I am going to replace with that.

 

[Broncobowsher]

That rear main seal leak, could be intake and valve covers leaking down to look like a rear main.
For what you describe, rebuild the stock carb. Super easy, super reliable. I have been known to remove the factory Holley 2-barrel from Internationals and upgrade them with a used Autolite 2-barrel.

For the leaks. It is a huge rabbet hole that you can fall into. My experience from a few years back. Got a 60K '77 F250. From the leaks it had the seller thought it had 160k on it. He hot it at an estate auction with no history. It leaked everywhere. All the cork gaskets were shot. Intake leaked, looked like yours. Oil pan dripped around the perimeter, left a rectangular shaped oil spot where ever I parked it. It had a ticking lifter, low on power. I figured it needed an overhaul but wasn't ready for that yet. But it leaked too much for a daily (or even weekend) driver.

I pulled the engine and vowed to not remove the heads. A compression test showed things were good enough. Technically I don't think it passed the withen 10% of each other, but they were withen 25% of each other. I just needed it to be good enough so I could drive it and see what it really wanted. So I did an engine stand gasket set. Valve covers, front and rear main seals, oil pan, intake. While in there I inspected a bunch of other stuff. Put in a set of bearings and a high volume pump, it should have had the bottom end redone but not now. Timing chain was really stretched, so a fresh one. A basic stock replacment non-emissions cam and lifters. Refused to take the heads off as I knew I would be going down a full rebuild if I did.

In the end I fixed a whole bunch of little things all at once. Not just the leaks, but the deffered maintenance items as well. Got it to the point I could actually drive and enjoy it. Plotted how I would like to do a true rebuild on the engine. Eventually sold it without doing the full rebuild. The freshening up was enough to make it a good daily driver. But that rabbit hole was tempting me. A few more bolts and the heads would have been off. Some flat top pistons for a little more compression. Oh so tempting.

Yes, there is a bit of work to pull the engine and put it on the stand. But once there the actual inspection and repairs were so much easier. And could be done better as well. I've screwed up setting an intake back on an engine while still under the hood many times. You just can't see the intake going down onto the engine very well. But on an engine stand, full access and see everything. Not fighting gravity, just flip the engine over to put the pan on. No crossmember in the way, or front axle, etc.

 

[tonytony9]

That rear main seal leak, could be intake and valve covers leaking down to look like a rear main.
For what you describe, rebuild the stock carb. Super easy, super reliable. I have been known to remove the factory Holley 2-barrel from Internationals and upgrade them with a used Autolite 2-barrel.

For the leaks. It is a huge rabbet hole that you can fall into. My experience from a few years back. Got a 60K '77 F250. From the leaks it had the seller thought it had 160k on it. He hot it at an estate auction with no history. It leaked everywhere. All the cork gaskets were shot. Intake leaked, looked like yours. Oil pan dripped around the perimeter, left a rectangular shaped oil spot where ever I parked it. It had a ticking lifter, low on power. I figured it needed an overhaul but wasn't ready for that yet. But it leaked too much for a daily (or even weekend) driver.

I pulled the engine and vowed to not remove the heads. A compression test showed things were good enough. Technically I don't think it passed the withen 10% of each other, but they were withen 25% of each other. I just needed it to be good enough so I could drive it and see what it really wanted. So I did an engine stand gasket set. Valve covers, front and rear main seals, oil pan, intake. While in there I inspected a bunch of other stuff. Put in a set of bearings and a high volume pump, it should have had the bottom end redone but not now. Timing chain was really stretched, so a fresh one. A basic stock replacment non-emissions cam and lifters. Refused to take the heads off as I knew I would be going down a full rebuild if I did.

In the end I fixed a whole bunch of little things all at once. Not just the leaks, but the deffered maintenance items as well. Got it to the point I could actually drive and enjoy it. Plotted how I would like to do a true rebuild on the engine. Eventually sold it without doing the full rebuild. The freshening up was enough to make it a good daily driver. But that rabbit hole was tempting me. A few more bolts and the heads would have been off. Some flat top pistons for a little more compression. Oh so tempting.

Yes, there is a bit of work to pull the engine and put it on the stand. But once there the actual inspection and repairs were so much easier. And could be done better as well. I've screwed up setting an intake back on an engine while still under the hood many times. You just can't see the intake going down onto the engine very well. But on an engine stand, full access and see everything. Not fighting gravity, just flip the engine over to put the pan on. No crossmember in the way, or front axle, etc.

Great story, I enjoyed reading it. Interesting enough, I have no drips on the floor; I have let it sit plenty of times, after a few times, various locations. Actually, the only drip is from the steering stabilized (next on the list along with steering instruments).

Accelerator pump covers a notorious for not being flat, and leaking.
Remove cover and flatten with a piece of fine emory cloth on a flat surface (I use table saw top).

Good idea! If it aint broke..............

I just reread this and I forgot to add the step about changing the accelerator pump diaphragm, also four screws on the front of the carb.

It's been 20 or so years since I did one!

I want to thank you all of the advice and information. This morning I used my carb rebuild kit from Auto Zone and was able to stop the leaking gas from the accelerator pump. Took it on a long drive today, not gas smell no new leakage! Its back on the road. Exciting day. Cleaned it up the best I could, next step will be a full rebuild/clean down the line. For now, it is not broken, so I am not fixing.

 

[73azbronco]

try and ID where the oil is from. You said intake, do you have idle or power problems indicating possible vacuum leak? I bet not. Dizzy is gunky because front seal may be leaking, head, maybe intake..

 

[tonytony9]

try and ID where the oil is from. You said intake, do you have idle or power problems indicating possible vacuum leak? I bet not. Dizzy is gunky because front seal may be leaking, head, maybe intake..

Agreed a bit ambiguous. Next step is replacing the radiator and cleaning the engine. It will be easier for me to see where leaks are coming from that way.

 

[m_m70]

Next step is replacing the radiator

Great! Make sure you flush the crap out of the block too.

cleaning the engine. It will be easier for me to see where leaks are coming from that way.

Yeah I'd be spraying that down with some heavy degreaser and letting it soak then spray it down. Probably going to take a few rounds of that. Obviously avoid getting water around the carb and distributor cap. I usually just cover with plastic bags (gallon freezer bags secured with a small bungee works well).

Actually, the only drip is from the steering stabilized (next on the list along with steering instruments).

Not sure that would be your leak. Lots of stuff above that can & will leak down on all the front end parts. Like above, clean it all up and see what's making the mess.

Took it on a long drive today, not gas smell no new leakage! Its back on the road. Exciting day.

That's great!!!! How long has it been off the road??