Rebuilding 1979 GS 1000 front caliper problems

[Topcat]

My 15,000 mile GS had the right front caliper start leaking and wiping the rotor.I ordered OEM Suzuki parts to rebuild it from Westfield Powersports but when i installed the new o-ring for the piston into the caliper body it would buckle and not lay down flat like it was too big. I tried putting it in the freezer but that did not help.
Any suggestions or recommendations on what to do to get this caliper properly re-built ?
Does anyone have or know of a rebuilding service ?
Thanks in advance !

Peace WildBill

[oldGSfan]

Here's a guess - when I was rebuilding my 79's brakes I bought the wrong part number 59307-45021. Partzilla had calipers for both 'C' and the 'EC' listed under the GS1000EN page and I wasn't paying close enough attention when I ordered. The 'C' must be the larger single caliper. I think the correct number is 59107-34021 but double check as it's been a while.

[Trills]

I just rebuilt both front calipers this weekend on my '79 GS1000. The seal part number should be 59107-34021 and although it might seem a bit big when doing the install, once it's in the groove it will fit like a glove. It sounds like you may have the wrong seal. These calipers are not too difficult to rebuild providing you have some basic tools and OEM parts.

[Grimly]

Best thing to do with the 79 calipers is heft one in the hand to get a feel of the weight.
Then punt it as far as possible into the ocean.
Replace with 80-on calipers as a straight swap.

[salty_monk]

I'm with Grim on this one...

[oldGSfan]

Best thing to do with the 79 calipers is heft one in the hand to get a feel of the weight.
Then punt it as far as possible into the ocean.
Replace with 80-on calipers as a straight swap.

That sure seems logical but somehow I got my '79 stopping really well, better than my '82 1100 turbo. Maybe the 100 HP difference is the thing. It takes a firm squeeze but the 79's are strong and right to the edge it's predictable. I was surprised.

[Grimly]

That sure seems logical but somehow I got my '79 stopping really well, better than my '82 1100 turbo. Maybe the 100 HP difference is the thing. It takes a firm squeeze but the 79's are strong and right to the edge it's predictable. I was surprised.

Apart from them never being all that good in the dry and atrocious in the wet, I was actually going to rebuild them a few years ago.
Then, when I stripped them I discovered serious corrosion internally, in the casting that holds them together. Under heavy braking there was a very good chance one (or both) of them might have cracked, leaving me with no brakes.
That's why I hate them.

[Topcat]

My calipers are perfect and not corroded....i will check the part#'s on the o-rings that i got....hopefully i got the wrong ones. As described above.....i love the brakes on my GS....good stopping power and very predictable in application....

Peace WildBill

[Big T]

Here's a guess - when I was rebuilding my 79's brakes I bought the wrong part number 59307-45021. Partzilla had calipers for both 'C' and the 'EC' listed under the GS1000EN page and I wasn't paying close enough attention when I ordered. The 'C' must be the larger single caliper. I think the correct number is 59107-34021 but double check as it's been a while.

The single disc models in 78 and 79 do have a larger piston than the E double disc models.

If the groove in the caliper is clean, the correct seal should pop right in.

Naturally, the seal should fit snugly around the piston

[Topcat]

Ok....i just went and looked at the piston seals i got and the bags are numbered 59307-45021.......i will order the 59107-34021 piston seals and see how they fit.

Anyone need the two i have ? $5.00 for the pair mailed to you for free.

I appreciate all the help from you all !

Peace WildBillIM003090.jpg

[oldGSfan]

Ok....i just went and looked at the piston seals i got and the bags are numbered 59307-45021.......i will order the 59107-34021 piston seals and see how they fit.

Anyone need the two i have ? $5.00 for the pair mailed to you for free.

I appreciate all the help from you all !

Peace WildBill

Retracing my steps - I offered up mine as spare and had one taker, still have one in a box somewhere. Glad to be of help. Bike looks a lot like mine, except I don't have that grab rail, and have a V&H. Had a Kerker on my 82 Katana, sounded great.

[Topcat]

Thanks everyone ! I now have the right seals.

Peace WildBill

[kochic]

Ok....i just went and looked at the piston seals i got and the bags are numbered 59307-45021.......i will order the 59107-34021 piston seals and see how they fit.

Anyone need the two i have ? $5.00 for the pair mailed to you for free.

I appreciate all the help from you all !

Peace WildBillIM003090.jpg

Hi, I will take the seals if you still have them.
Thanks,
Marc