12 replies to this topic

[trashy]

I bought a '90 Mini Cooper RSP this week and decided to give it a full service.

 

Everything was going well until I decided to flush the coolant, change the thermostat, etc.

 

Bottom rad hose came off (eventually).

 

Thermostat housing was a nightmare, all three bolts sheared, two in the housing, one below.

 

Also noticed that the heater take-off has corroded badly and is holed.

 

So, how do I get the bolts out and the sandwich plate off?  Any guidance appreciated!

Edited by trashy, 30 August 2021 - 12:50 PM.

[mab01uk]

If you remove the alloy thermostat sandwich plate housing from the cylinder head it will be a lot easier to remove the sheared studs remains. A new sandwich plate will probably be needed if it is corroded in position and has to be cut/damaged to remove it....but you will need a new one anyway because of the heater take off corrosion !

 

THERMOSTAT SANDWICH PLATE CARB COOPERS HAS FAN SWITCH HOLE:-

http://www.minispare...c/PEM10036.aspx

THERMOSTAT SANDWICH PLATE WITH OUTLET

http://www.minispare...c/PEG10002.aspx

THERMOSTAT HOUSING LARGE BORE - ALL CARB COOPERS

http://www.minispare...10.aspx|Back to

 

These TMF links below may also help:-

http://www.theminifo...t-housing-bolt/

http://www.theminifo...g-bolt-sheared/

http://www.theminifo...deas-to-remove/

http://www.theminifo...ing-bolt-stuck/

Edited by mab01uk, 03 October 2020 - 02:26 PM.

[trashy]

Thanks, what's the best way to remove the sandwich plate?  I ended up hack-sawing the thermostat housing off as it was so firmly corroded in place!

[mab01uk]

Have a read of the links above for various ideas on removal but you may have to also do some hack sawing (or multi-tool with metal blade) of the sandwich plate to weaken it and aid removal if it is corroded in position, just be very careful not to damage the cylinder head surfaces below and try to retain all the bolt studs sticking out head for later removal. Like the thermostat housing the sandwich plate is soft alloy. You can sacrifice the sandwich plate as it is badly corroded and easily replaced with a new part.

Edited by mab01uk, 03 October 2020 - 02:37 PM.

[the.stroker]

Get yourself over to DSN classics once your ready to replace the housing, a nice billet alloy replacement will do nicely!

https://www.dsnclass...ne-accessories/

[trashy]

Thank - got the sandwich plate off, studs intact and no damage to the head :)

 

Not sure how to tackle the bolts - all three have some thread left.  Perhaps double nut them?  I've used lots of Plusgas but not sure much has penetrated.

Edited by trashy, 30 August 2021 - 12:48 PM.

[mab01uk]

Well done, time to have a think about the best way of easing them out without shearing them off flush with the head. Some ideas and methods in the links above may help, also the application of some heat on the studs and then more Plusgas soaking overnight if you can wait that long. Be careful if you apply heat as some of the antifreeze still in the head/block can be flammable.

 

Quote from the links above:-

"You heat the bolt, that expands and contracts in the thread hole, breaking any rusty or stuck parts, and then you work the bolt out slowly with some grips whilst cool/cooling.
I'd try the two nut technique first, use heat as a last resort, as mentioned above have a fire extinguisher handy!"

 

Another alternative to grips:-

"The Laser Impact Stud Extractor 1/2" Drive is used with air tools and standard hand tools with 6-12mm studs. Made from Chrome Vanadium with Chrome Molybdenum jaws, it can take on rusted, damaged, broken or stripped studs."

https://www.halfords...ive-121932.html

Edited by mab01uk, 03 October 2020 - 05:15 PM.

[kit352]

I would use heat first without a doubt.

[alex-95]

I would heat them up, spray them with penetrating fluid and get a set of these irwin stud/bolt extractors. https://www.machinem...BSABEgL3bvD_BwE

[trashy]

Thanks so much, I've ordered some more MAPP gas for my blow torch, some 5/16" unc half nuts and another can of PlusGas!  They won't arrive until mid-week so I shall have to resist having a go until then!

 

I might also order the stud extractor, just a bit worried that I might apply too much force and shear them again.

 

I've already got a set of the Irwin sockets, used them on bolts before, didn't know I could use them on these shafts - good call.

by the way, how do I prepare the surface when I fit the new sandwich plate to the head?  Is there a gasket or gasket sealant used?

Edited by trashy, 03 October 2020 - 06:07 PM.

[AlasdairM]

Hi trashy,

I have a 1990 cooper too, and this exact same problem happened to me too.

I ended up using lots of WD-40, and a miniature creme-brûlée burner from amazon to heat up the studs. With a set of mole grips, the studs started turning quite easily. As you’ve said though, just use caution!

As for prepping the surface, I just used a Stanley blade after cleaning it up, then used the paper gasket which comes with the sandwich plate. No need to use gasket sealer etc.

[cal844]

Personally I use gasket sealer on paper gaskets. Just a very fine smear, nothing drastic to aid sealing

[trashy]

Thanks everyone, bolts removed and new items fitted.  Used the blow torch and Irwin extractor to get the bolts started and then mole grips and lots of time and PlusGas :)

 

 

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