Any tips on re-fitting the dust seal on the caliper piston?

[Austblue]

When I pulled the brakes off my 81sh their condition gave me the impression they hadn't been serviced by any of the po's so I started giving the right side caliper a birthday flushing all the crusty fluid out and cleaning all the crud off the caliper itself. I removed the dust boot to get all the crap from behind it and now I'm really struggling to get it back on. Are there any tips or tricks to this? The diameter of the dust boot is larger than the seat so it wants to bunch up and pop off where it seats on the caliper. Getting it on the piston is fine but the skirt obviously needs to sit on the caliper and I'm not seeing how this is done.

Any help is appreciated.

Adding some pics but its not easy to photograph

This pic is an extra just showing the level of crud in behind the piston. Glad I cleaned it all out!

 

[jchrisk1]

Just buy the rebuild kit. Comes with new one that goes on without a fight. Also has a new o-ring for the piston.

 

[angus67]

looks like he has the kit allready.
i had trouble with that too, the metal ring goes on the outter part, i just kept workin it untill it stayed on. the brake pads will hold it on once its all back together.

 

[Austblue]

Thanks for the help so far.

I'm actually just reusing the seals that were on it since visibly they were in good condition. So you're saying that the rebuild kit dust boot is easy to fit? That's $42 for the two of them so if I'd rather be sure that's the best way to go before scrapping the seals and cash only to find they're just as hard to fit. Also I've been told not to buy rubber components from Mikes, what are their rebuild kits like? Is there a better place to buy from?

 

[kvanderploeg]

You're probably just not sliding the spring down far enough on the boot. Once you get it all the way down, it will catch the lip and stay down there.

Kent

 

[gggGary]

Did you use brake parts cleaner on the dust boot? Brake parts cleaner is to be used on metal parts only, do not get it on the rubber parts the rubber will grow and pretty much be trashed. The piston goes in first then the dust boot, not sure from the pics you are doing it that way. you have to kind of expand the metal ring hold the ends apart and slide the middle of the ring over the boot at the back where you can't see it then the end get dropped on the boot out front where you can see what you are doing, yeah it's a bit tricky. It's important to remove the rubber wiper from the caliper body and get all the crap out from behind it too. I like to grab a chunk of heavy solid copper house wire, kind of hammer and file the end square and put a 90 bend in it to use as a scraper gets the gunk out of the groove without scoring the aluminum.

 

[Austblue]

Thanks again everyone. By the 'rubber wiper' do you mean the piston seal that sits inside the bore like a square faced 'o' ring?

I only cleaned the rubber boot using spit and paper towel but I'm inclined to think that since the fluid was in such junk condition and probably 30y.o the rubber could use renewing. For all I now the p.o could've used brake cleaner to clean it whilst it was assembled because I'm pretty sure that it has expanded.

 

[gggGary]

yeah the square piston seal. That's what I meant.

 

[Austblue]

I should've closed this out - I bought the rebuild kit and it was clear that the dust boot I had had perished as the replacement went on quite simply.

Thank you all for the help.