1988 Carrera battery replacement

[mysocal911]

Originally Posted by Ned, NYNA11

Get a smaller one. Less PIA getting it in and the re is another threaded hole down there to fasten the hold down clamp.

Good idea, not only from the standpoint of the smaller size but also because the
larger batteries can over-stress the alternator when the battery has a very low
state of charge, e.g. especially the '82/'83 911SC alternator.

[NO LIFT]

Originally Posted by Ned, NYNA11

Get a smaller one. Less PIA getting it in and the re is another threaded hole down there to fasten the hold down clamp.

Anyone know the alternative group size for a battery that utilizes the other threaded hole?

[Nick Triesch]

My last interstate lasted over seven years. I just replaced with one just like it . Why would I buy anything else?

[MarkY]

Well before I can replace, I need to take the old one out. What a nightmare. I have the toolkit that came with my car. It had a long allen wrench that I was able to use to loosen the front bracket.

- do I remove this allen set screw completely?
- any idea on how to loosen the ground cable nut? I believe it is 12 mm but can't get a wrench on it to confirm. And if i could, I couldn't move the wrench. HELP is appreciated on how the hell to loosen this bolt so I can remove the cable clamp from the battery post.

Thanks

[Bob Kontak]

Originally Posted by msterling

My '88 had a monster Interstate battery (MTP-93 like yours) that was still good after 10yrs but the PO had installed it without connecting the vent tube.

I bought the Monstro 930 lead-acid battery from Sam's Club in Montrose early last year for my SC. About a buck and a quarter.

I have not connected the vent tube yet. However, I drive like a little girl for the most part. This spring I will install it. Gotta drill a hole, I believe. Thanks for the info.

[Bob Kontak]

Originally Posted by MarkY

- do I remove this allen set screw completely?

Yes, very tight quarters.

If you don't have sockets, get a good 3/8 set, even the better Harbor freight ones, and see if that can get a bite on the nut(s).

[MarkY]

Originally Posted by Bob Kontak

Yes, very tight quarters.

If you don't have sockets, get a good 3/8 set, even the better Harbor freight ones, and see if that can get a bit on the nut(s).

I was able to remove the bracket, and I can budge the battery a smidgen. I'll try and get enough room to get a socket on there. Anyone know what size? Looks like a 12mm. At this point I can get anything on the nut or the square head of the bolt.

[MarkY]

Here is what I'm up against:

[Bob Kontak]

13 MM. Saying this because they are mostly 10mm and 13mm. On all cars, pretty much.

Get a skinny set of metric wrenches. Skinny meaning wall thickness on the box part of the wrench. The big fat gear wrenches from Harbor Freight have too much thickness (probably) to allow the wrench to slide over the nut.

Check at your local auto parts store. I am thinking $30+ for a decent set. They will set you free.


Edit: Square head is meant to hold the bolt in place while you loosen the nut. It's all good. Just a little learning curve and a few $$ spent to get a few tools.

[msterling]

Usually a 1/2" wrench works on battery terminal nuts. Move it a teeny tiny bit, flip the wrench, move it another teeny tiny bit, rinse and repeat.

Re: using only metal hold downs and trays; the original clamp was metal but only held the battery by a ridge at the bottom of the battery case. A metal clamp over the top of the battery would certainly be stronger. I don't think there was anywhere near enough room to do that with the original humongo battery. Like the OP said, it is really shoe-horned in there. There is not really enough room to install a proper vent drain tube with the Interstate battery.

Re: Drain tubes There are drain holes below that have rubber grommets. A tube could be routed through one of them.

[db_cooper]

Originally Posted by MarkY

Here is what I'm up against:

I have a funny side wrench 13mm to get to that nut...the solution is to remove the 13mm head nut ground from the stud fitting on the inside fender and pull the battery with the ground cable still attached. Clean the ground stud on the fender and the nest of grounds that bolt there from other equipment too, while your there.

If the battery ground cable is old enough to vote..replace it with a new one from our host.

[db_cooper]

Originally Posted by NO LIFT

Anyone know the alternative group size for a battery that utilizes the other threaded hole?

I used a 48AGM-70..group 48..

Fits just fine..The AGM Deka is from Carquest .part number BAT 48AGM-70.three year non-prorated replacement guarantee. $156

[hastighet]

Just did the same last week. I went with a Sears Diehard advanced gold group 48. It's an AGM which means no leaking. Way easier to maneuver into the space and the mount works with a factory hole. I wound up taking out the front condenser fan to clean up the area due to a PO using a cheap battery and NOT connecting the drain. Seriously?

One note if you haven't done this before, use a box wrench and wrap the handle with friction tape. 1. it won't slip on you and most importantly, 2. you won't ground the positive terminal to the body when you're fussing with the nut. Didn't happen to me, but I've witnessed it.

[msterling]

Originally Posted by hastighet

Just did the same last week. I went with a Sears Diehard advanced gold group 48. It's an AGM which means no leaking. Way easier to maneuver into the space and the mount works with a factory hole. I wound up taking out the front condenser fan to clean up the area due to a PO using a cheap battery and NOT connecting the drain. Seriously?

One note if you haven't done this before, use a box wrench and wrap the handle with friction tape. 1. it won't slip on you and most importantly, 2. you won't ground the positive terminal to the body when you're fussing with the nut. Didn't happen to me, but I've witnessed it.

Just remove the negative terminal first and then the positive. When reconnecting; positive terminal first and install protective terminal cover BEFORE connecting the negative. "It could happen to you; it happened to me". If your wrench is shorter than the distance between terminals then the danger is somewhat reduced.

[rick-l]

Originally Posted by MarkY

Here is what I'm up against:

My standard 13 mm Craftsman combination wrench works just fine and I remove the cable a couple times a month. The box end only covers half the flats but that is more than enough.

Be sure to remove the negative cable first.

[aigel]

Originally Posted by hastighet

One note if you haven't done this before, use a box wrench and wrap the handle with friction tape. 1. it won't slip on you and most importantly, 2. you won't ground the positive terminal to the body when you're fussing with the nut. ...

You always disconnect the negative cable first to avoid shorting the positive to ground when disconnecting it. No wraps needed.

G

[beren]

Just installed an Interstate MTP-49/H8 in my 3.2 - was pretty tight getting that sucker in. All is good and it fired right up. PO did not have a vent line attached. I'll have to get one, but having some troubling finding one. Any sources that you all know of?

It didn't come with a vent tube.

[aigel]

The batteries should come with a vent line that goes on the bank of openings in the top of the battery. If not, there should be a standard round hole that you can push your existing nipple into. If you do not have a vent line, a trip to the auto parts store should yield a hose and a nipple that fits into your existing lines. You can even just make this from scratch and find a grommet to the outside.

4 yrs old this month (Battery and Spark Plugs questions)


HTH,

G

[msterling]

Originally Posted by beren

Just installed an Interstate MTP-49/H8 in my 3.2 - was pretty tight getting that sucker in. All is good and it fired right up. PO did not have a vent line attached. I'll have to get one, but having some troubling finding one. Any sources that you all know of?

It didn't come with a vent tube.

I believe this is the correct vent tube kit for your battery. It seems like it should have come with it. Maybe contact your dealer that sold it to you. The right-angle bend and the oval shape are hard to duplicate.

[rick-l]

Originally Posted by mysocal911

Good idea, not only from the standpoint of the smaller size but also because the
larger batteries can over-stress the alternator when the battery has a very low
state of charge, e.g. especially the '82/'83 911SC alternator.

Do you have any evidence of this?