Pennock's Fiero Forum
  Technical Discussion & Questions
  How to repair water pump bolt hole that has stripped.?

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
How to repair water pump bolt hole that has stripped.? by ltlfrari
Started on: 08-03-2014 12:29 PM
Replies: 13 (5238 views)
Last post by: ltlfrari on 08-31-2014 05:51 PM
ltlfrari
Member
Posts: 5310
From: Wake Forest,NC,USA
Registered: Jan 2002


Feedback score: (4)
Leave feedback





Total ratings: 127
Rate this member

Report this Post08-03-2014 12:29 PM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
I am replacing the water pump on my 2.8 for the 2nd time (had a leak after the first time sigh!) and when torquing bolt number 9 (one of the small ones) in this diagram:



I found that the threads in the hole are stripped.
Now my leak was from bolt number 4 which goes into the jacket (a load of coolant came out when I removed it anyway) but my question is this:

Should I repair this bolt hole and if so, what is the best way to do that? Bear in mind that the engine is still in the car and this hole is opposite the lower frame rail so getting a drill in there to drill and retap and/or put a helicoil or similar in there is not that easy as there's not a lot of space between the face of the timing cover and the frame rail (short of lifting the engine a bit which is an option I guess).
It seems to me the simplest way to fix would be to drill it out (somehow) and tap to a slightly larger size, drill out the pump hole and use a larger bolt.
Another alternative might be to insert a stud in there (but how to secure) and then use a nut on the stud in place of a bolt at that location.

Or, should I just leave it?

Oh, I am planning on using the black permatex instant gasket stuff for the gasket instead of a regular gasket and rtv (although that worked fine before). Thoughts on that as well?

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

IP: Logged
PFF
System Bot
84fiero123
Member
Posts: 29950
From: farmington, maine usa
Registered: Oct 2004


Feedback score: N/A
Leave feedback





Total ratings: 325
Rate this member

Report this Post08-03-2014 03:55 PM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
Borrow or rent a angle drill and helicoil it. sorry I got nothing better. Or if you have an angle die grinder you might be able to get that in there to drill it.

Good luck, you are going to need it.

Steve

------------------
Technology is great when it works,
and one big pain in the ass when it doesn't



Detroit iron rules all the rest are just toys.

IP: Logged
Patrick
Member
Posts: 30711
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 443
Rate this member

Report this Post08-03-2014 04:13 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ltlfrari:

...and when torquing bolt number 9 (one of the small ones)...I found that the threads in the hole are stripped.


This probably won't help you a whole lot at this point, but anyone replacing a water pump needs to be aware that those small bolts are being screwed into soft aluminum. They don't need to be tightened very much.

Considering the location of those stripped threads (and the difficult access), I'd probably use a lag bolt which is just large enough to dig into the walls of the (now stripped) threaded hole in the aluminum timing cover. If need be, drill the hole in the water pump a little larger to allow the lag bolt to pass through it.



Yes, I know that's not the "proper" way to do the repair, but IMO it's sometimes acceptable to improvise depending on the situation... as long as the repair will actually work.

 
quote
Originally posted by ltlfrari:

Oh, I am planning on using the black permatex instant gasket stuff for the gasket instead of a regular gasket and rtv (although that worked fine before). Thoughts on that as well?


IMO, anything which originally required a gasket should still have a gasket installed... with sealer used on both sides if required. I'm old-school though, so others may have a different opinion.

[This message has been edited by Patrick (edited 08-03-2014).]

IP: Logged
lordbg0205
Member
Posts: 236
From: cincinnati, oh
Registered: Nov 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post08-03-2014 07:47 PM Click Here to See the Profile for lordbg0205Click Here to Email lordbg0205Send a Private Message to lordbg0205Edit/Delete MessageReply w/QuoteDirect Link to This Post
Been there done that, pull the timing cover, as you probably broke the seal due to replacing the pump. Clean up the surfaces, start taking some measurements and get to a fastenal and get some keyserts. You will drill out the threads, rethread it, insert the keysert and tap them to lockem. The come in various grades of steel. Did all mine about a year ago, threw out all those torx and used allen bolts that are grade 8. Overkill im sure because the bolts dont hold much, but i can change my waterpump in about 30 mins and ensure proper torque all the way around.
IP: Logged
Tooshea
Member
Posts: 43
From: Ashburn, VA
Registered: Feb 2014


Feedback score: N/A
Leave feedback

Rate this member

Report this Post08-04-2014 07:32 PM Click Here to See the Profile for ToosheaClick Here to Email ToosheaSend a Private Message to ToosheaEdit/Delete MessageReply w/QuoteDirect Link to This Post
I feel your pain.. Instead of stripping the threads someone before me stripped the Torx head then when I was using a bolt remover I snapped the head clean off. :O... Then I did it to another bolt.. Then it took FOREVER to remove the bolts from the block.. What a pain..

Not an easy job when the engine is in sideways.. ..

------------------
Tim and Lynn
1987 Fastback GT in restore mode..

IP: Logged
TONY_C
Member
Posts: 2747
From: North Bellmore, NY 11710
Registered: May 2001


Feedback score: (2)
Leave feedback

Rate this member

Report this Post08-04-2014 07:43 PM Click Here to See the Profile for TONY_CSend a Private Message to TONY_CEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had bolt #1 in your picture strip out the head. i had to cut the head off with a cutoff wheel to get the pump off. That bolt would not budge even when I could get a vise grip on it. I put the new pump on with the bolt still in and it didn't leak. I realize your bolt is on the bottom so you may not be so lucky as leaks go but if you really want to tap it out and put a helicoil in you may be able to lower the rear of the cradle enough to work in the wheel well. You'll have to disconnect the three upper strut bolts and some other stuff but it swings down fairly easily. I did the timing gear on my Duke working thru the wheel well.
IP: Logged
Patrick
Member
Posts: 30711
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 443
Rate this member

Report this Post08-04-2014 08:10 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by TONY_C:

That bolt would not budge even when I could get a vise grip on it.


Makes you wish that all previous owners (and/or their mechanics) used anti-seize on every bolt.
IP: Logged
TONY_C
Member
Posts: 2747
From: North Bellmore, NY 11710
Registered: May 2001


Feedback score: (2)
Leave feedback

Rate this member

Report this Post08-04-2014 08:52 PM Click Here to See the Profile for TONY_CSend a Private Message to TONY_CEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Makes you wish that all previous owners (and/or their mechanics) used anti-seize on every bolt.


Yeah but I'm pretty sure it was the original pump though. Forgot to add, make sure you get water pump with the metal impeller.
IP: Logged
Patrick
Member
Posts: 30711
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 443
Rate this member

Report this Post08-04-2014 09:04 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by TONY_C:

Yeah but I'm pretty sure it was the original pump though.


Okay fine... blame Pontiac then.
IP: Logged
Dennis LaGrua
Member
Posts: 13640
From: Hillsborough, NJ U.S.A.
Registered: May 2000


Feedback score:    (13)
Leave feedback





Total ratings: 321
Rate this member

Report this Post08-05-2014 08:27 AM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
An improved method of thread repair and stronger than a Helicoil is called a Timesert. I know an engine rebuilder that has used these to hold the heads in place on the 4.9L Caddy engine that he has rebuilt. When rebuilding those bolts are famous for stripping the threads upon removal. Point is that it happens all the time.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

IP: Logged
ltlfrari
Member
Posts: 5310
From: Wake Forest,NC,USA
Registered: Jan 2002


Feedback score: (4)
Leave feedback





Total ratings: 127
Rate this member

Report this Post08-05-2014 08:41 AM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
One problem is that this hole is only about 3/8 of an inch deep, if that so there's not a lot of room depth wise to work with to put an insert into.
These bolts only take 7 ft lb of torque so they are not really doing a lot and given that there's a bolt on either side I am thinking I might just put the pump back on without that bolt and see if it holds. At worst I'll have to pull it again and fix it properly.

Oh, and I've never seen a pump with a plastic impeller yet and I've done a few over the years.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

IP: Logged
PFF
System Bot
Dennis LaGrua
Member
Posts: 13640
From: Hillsborough, NJ U.S.A.
Registered: May 2000


Feedback score:    (13)
Leave feedback





Total ratings: 321
Rate this member

Report this Post08-05-2014 06:24 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ltlfrari:

One problem is that this hole is only about 3/8 of an inch deep, if that so there's not a lot of room depth wise to work with to put an insert into.
These bolts only take 7 ft lb of torque so they are not really doing a lot and given that there's a bolt on either side I am thinking I might just put the pump back on without that bolt and see if it holds. At worst I'll have to pull it again and fix it properly.

Oh, and I've never seen a pump with a plastic impeller yet and I've done a few over the years.



Are you sure that the bolt hole is only 3/8" deep or is an old bolt broken off in there? If in fact the bolt hole is 3/8" deep then determine if it can be drilled deeper to allow a helicoil or timesert. In the very worst case tack weld or braze a stud into the hole. You can also try JB Weld as its better than nothing. If you torque to 7 ft lbs then it may hold.


IP: Logged
ltlfrari
Member
Posts: 5310
From: Wake Forest,NC,USA
Registered: Jan 2002


Feedback score: (4)
Leave feedback





Total ratings: 127
Rate this member

Report this Post08-09-2014 05:11 PM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hole is actually 5/8 inch deep. I took a look at it today and decided to fix it. The original bolt is 6mmx1.0 pitch and after taking a few measurements I figured an 8mmx1.25 bolt would fit. I also happened to have a set of taps of that size , including a plug tap, and drills so I tackled the job today.
I had to 'drill' it out be hand because there's no way to get a drill or even my right angle adapter in there between the face of the timing cover and the lower frame rail and I was not in the mood to unbolt the engine mount, drag my cherry picker out from under the house and assemble it and lift the engine. So I welded a nut onto the end of a drill bit and used one hand to keep things straight and the other hand to turn the drill with a wrench. Since I was only really taking off the old and now mostly stripped threads it was not too hard.
Then I tapped the hole out. Had to use a wrench on the tap because the hole is too close to the engine pulley to get the tap handle on there and turn it.
After that I drilled out the hole in the pump to clear the bolt.
I screwed a bolt in there and measured how far it went in and I've got 3/8 inch of usable threads so while I cannot tighten it up real tight I can at least get about as much tension on it as it should have (7 ft lbs).
I just need to get a bolt now and cut it to length.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

[This message has been edited by ltlfrari (edited 08-10-2014).]

IP: Logged
ltlfrari
Member
Posts: 5310
From: Wake Forest,NC,USA
Registered: Jan 2002


Feedback score: (4)
Leave feedback





Total ratings: 127
Rate this member

Report this Post08-31-2014 05:51 PM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
Note to self. Next time (if there ever is a next time!) install the modified bolt first. I left it to last and of course my hand drilled hole did not quite line up.
After several attempts the gasket was getting to be a mess so I just went with RTV on the faces and so far at least, it seems to be holding up fine with no leaks.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock