Update: Realised the importance of DIY. During the radiator flush, I noticed something unusual. The front crossmember has two holes, on either side, which is covered by a film. The film on the LH side was missing, and I saw some major rust inside. A peek into the member with my trusted endoscope worsened my fears. The whole crossmember had become hollow from inside and was filled with rust flakes.
I took GG to MASS, and the mechanic inspected everything, and as the crossmember was pretty solid from outside, he said it's still good and I shouldn't worry about the rust inside.
Still, what I had seen through endoscope was disturbing me, and I asked my SA to open a jobcard and give me a new crossmember for a day or two. I wasn't impressed with the rust proofing on the member, and wanted to provide it some additional layer of coating. My plan was: We'll remove the member from the car, if its fine, we'll install the new coated one and refurbish the old one for future.
I brought the member home, and prepped it for coating. That's when I see the internals of the member showing some surface rust and dirt. Took out my endoscope again, and scanned the internals. The surface rust wasn't major and was only at some places. Endoscope gives a nice idea about the things hidden from naked eye, and that ensures proper planning and execution.
My treatment included:
1. Washing the member and internals with pressurised water to remove all dust inside. Drying it.
2. Since the rust wasn't a major one, I used Rust converter to stabilise it, before painting.
3. External treatment: Wipe down the surface with Rapid Cleaner. Close the two holes by sticking the OEM film, and Spray two layers of Zinc. Then a layer of 3M Body Schutz, and finally a layer of bitumen(aka Rock Guard). The rock guard specially is a very thick, rough coating with rubbery texture.
4. Interal treatment: Rust converter-2 Layers of Zinc sprayed using air gun(what painters use)-Cavity Wax.
The whole process needed 5 days, as I used to carry these jobs only after office hours, and that allowed sufficient time to each layer for curing.
The SA was very happy on seeing the final product.
Another headache was that most MASS remove the engine and gearbox from the chassis to change the front crossmember, as the engine member rests directly on it, and one of the three mounts is also connected to the member. I asked my SA if its possible to change the member without removing the engine, and he said YES!!
But as soon as we removed the bumper, I was shocked!! The coolant was leaking. I was sure I had damaged the radiator while cleaning, and was mentally calculating the additional cost of radiator. But my SA was quick to identify the source of the leak even without removing the radiator, and he was damn right. The clamp of the lower radiator hose was hitting the member causing the hose to bend a bit. Experience counts!!
Time for some pics.
The new crossmember. Part No: 71100M84010. This particular member is recommended only for 5S 800, although other cars can use it too. Difference: As 5 Speed 800 has a radiator drain plug, this member has an extra hole for that.
Liqui Moly Rapid Cleaner for cleaning the surface before painting
Cleaned
Surface rust inside the new member due to lack of protection
Rust Converter
Internals liberally coated with rust converter
Externals receive a layer of Zinc
Liqui Moly Zinc-Alu Spray
Products used
Conversion done. Treated with Zinc too
Coolant leak
Mechanic still not convinced if the member needs replacement
The way they avoided removal of engine and gearbox
Loads of rust flakes which came out of the old member. The mechanic is shocked!
Some more flakes visible
New Vs Old. Notice the rough finish which rockguard provides.
More flakes. The mechanic was eventually happy we changed the member, as it had become hollow from inside.
Y5A: This was the internal R&D code for 5 Speed 800.
GG receives a well deserved foam wash
Regards,
Shashi