S38 throttle body bellows

[Landsnark]

Hi gang -

The M6 is coming along nicely - completed inspection 2, changed out a bunch of PS hoses, O2 sensor, and just put a new set of injectors in. Running much better, but not perfect.

I noticed that a couple of the rubber bellows between the accumulator and the throttle bodies were cracked and decided to change them all out. I've managed to pull the entire accumulator assembly off, including the horns and bellows, but I'm puzzled as to how to get these rubber parts off. The small end of the bellow is too small to go over the horn of the velocity stack and also too small to stretch over the mounting flange on the other end.

Is there a secret method for replacing these? Anyone here done it before? I suspect that I am struggling because the old ones are hard as a rock and that getting the new (presumably stretchier) ones on will go easier. But before I do something drastic like cut off the old ones I thought I'd ask.

Thanks in advance for any guidance!

[GazM3]

Hey there. U can replace the rubber reducers that connect the throttle bodies to the plenum with silicone reducers. (Got mine form siliconeintakes.com). They are slighly longer than oem which have the benifit of bringing the Bellingham trumpet about 10mm further away. Gives a nice but small lift in power also.

To remove I normally take the trumpet section off with them still connected by the rubber “bellows”. U have to be careful not to drop the shiny nuts and washers. I normally use a strong magnet.

[88m6]

I too am wondering same thing.
Had to change oil pressure switch so of course have to remove intake which while off am getting it powderedcoated n while I'm at it removed trumpets to clean cosmoline off them ,clamps ,bellows and while at it thinking about switching to silicone intakes but those bellows have hardened and I'lcant see a what to remove without cracking or ripping them over trumpet flair.
I am also going to paint the trumpets with a silver metallic n clear so either way rubber has to come off. Going to try to heat and dish soap n see what happens.

Suggestions appreciated

[Landsnark]

I too thought that heat might be the answer. I heated up a small saucepan of water and stood the trumpets/bellows in it for 20 seconds or so.

The first one came off with little struggle so I thought AHA! But the rest tore during removal and in fact after a couple I didn't even bother with the water. They were so dried up and aged that they could be rather easily torn off in chunks. So no help for anyone trying to reuse...

But now the hard part. I had already purchased a set of OEM replacements. Will they tear when I try to put them on? Does hot water mess with the rubber and make it more brittle? Maybe a little oil on the horn would help? Not sure, so I will research further before forcing the issue. Hopefully others will chime in!

PS - Thanks GAZ - wish I would have known about the silicone boots before I purchased the OEMs I'm certain that they would be stretchier.

[wattsmonkey]

Assuming S38 bellows are the same as M88, new ones will stretch over no problem at all.

[Landsnark]

As near as I can tell from REALOEM, they are indeed the same. REALOEM insists that these cars (M6, M635, 635csi) either have M30 or S38 mills - no M88. We all know that's wrong, but simply looking up the bellows PN for M6 and M635 yields the same number.

So maybe just force it. I'm thinking I'll warm it with a heat gun a bit first....

Thanks

[Landsnark]

Wattsmonkey, you were right.

I did soften them up a bit with a heat gun on LOW, but no lube was needed.



To others attempting this - don't try to save your 30 year old bellows. They've lost all of their plasticizers and not survive the process.

Thanks, everyone!

[Da_Hose]

I went with silicone reducers too. They slipped over the trumpet just fine. Unbolt the trumpets, and everything comes off together just fine.

Jose

[88m6]

I too have just ordered silicone ones3.25-2.25 an expect them next week. Was going to with 2.5 but they are out n don't expect more til after may30 sometime. Didn't feel like waiting as my intake will be back from new wrinkle from powder coat shop around corner Tuesday n want it all back together so I can move on to next part of project.
Started when oil pressure switch had to be replaced so off intake came to get at it,then what the heck get intake redone,then what the heck,new seals for trumpets, then what the heck new silicone intakes, then what the heck and all new hoses under there while I have access then... stop me

I left my trumpet assy in hood of truck for a hour and they all came off relatively easy. Tore one just a tad around clamp area but reusable . So that's why I just ordered OE size not as bad as I thought after reading posts.
Will post pics when all back together .