1150 rear shock rebuild (preload)

[Guest]

Yes I searched, but info about this was limited.

1. In the process of installing a heavier rear spring I discovered that the preload wasn't working. There's 3 O-Rings inside which I'll just replace, but how much ATF do I put back in? I found an old thread describing the procedure to draw the fluid in, but it doesn't give an idea of ho w much.

2> Is there anything else I need to be aware of?

Thanks

[Colin Green]

Yes I searched, but info about this was limited.

1. In the process of installing a heavier rear spring I discovered that the preload wasn't working. There's 3 O-Rings inside which I'll just replace, but how much ATF do I put back in? I found an old thread describing the procedure to draw the fluid in, but it doesn't give an idea of ho w much.

2> Is there anything else I need to be aware of?

Thanks

I'll be putting this thread on my watch list. I thought they wern't re-buildable.

[cableguy]

The shock itself isn't, but I meant the preload adjuster that the shock body fits into. Maybe rebuild wasn't the right word, but there are 3 o-rings inside the "plunger sleeve", and I'll find those somewhere and replace them. Suzuki fiche lists the shock/spring/preload adjuster as an assembly, but they do come apart rather easily (once the spring is compressed of course).

[cableguy]

I figured it out.
I used brake fluid instead of ATF because I realized this is a hydraulic application.
Compress and remove the spring
The preloader just slides off
The inner sleeve pushes out toward the bottom. Thumb pressure was enough for me. Set the sleeve aside.
Look in the main body and you'll see the O-rings. There are 3 different thicknesses, so keep track of where they go.
There's no listing for these suckers so I had to get creative. I finally found them at a heavy trucking repair shop that had a hydraulic department. They were able to match them up.
I tried to flush out the old fluid by blowing through the hose but not a whole lot came out. I think the hole(s) are pretty small.
To refill the system I used a syringe. You can find them at auto parts stores and hardware stores.
I refilled the main body first. Back the adjuster knob all the way out, then use the syringe to inject brake fluid.
Next fill the hose. You can't just screw it into the body and inject fluid because the inner diameter is too small for the air bubbles plus syringe, so I put one end in a dish filled with brake fluid and injected into the other end until the air bubbles stopped, then quickly threaded the end on to the body. That's as good as I could get it.

I think there might be a little air still in there because the pressure only started to build at about 2 on the adjuster scale. I set it at 3 and hopefully I'm good with that and the stiffer spring I swapped in.

[1150bob]

Brake fluid?
Get back to us on how that goes for you.

[cableguy]

Because you're curious, or is that being sarcastic? If the latter, please enlighten, because I don't have it all back together yet and it would be great to know in case I need to replace it with something else.

If the former, I don't know yet I'm still finishing paint and other electrical diagnosis/repairs.

Thanks

[salty_monk]

Brake fluid is a non compressible oil like liquid... it should work fine but it's Hydroscopic so might take on water over time & there may be some reaction with the seals as the glycol could react with what was in there before. (this is why they recommend a minimum of a good flush but preferably to change all the seals on brake systems converted from Dot 4 to Dot 5. (Note DOT 5 is completely different to DOT 4 or DOT 5.1)

I would use a hydraulic oil (Jack oil would work) or if it has to be brake fluid then perhaps the DOT 5 silicon one.

[1150bob]

http://www.gixxerplanet.com/home/sho...rear-shock-oil. Try this link. Brake fluid is hydrophilic, meaning it will bond well with water,even the moisture in the air. I've seen lots of brake systems that have had engine oils or hydraulic oils added(mistake or on purpose)when only Brake fluid was specified,and all seals are ruined. Some equipments brake systems use hydraulic oil or transmission oils and if the seals are for a brake fluid(dot3) you get ruined seals. Usually the seals become swelled and soft ,with the consistency of jello. So a little more searching on the subject might save you time and grief.
Just saying not all seals are compatible with brake fluid.

[cableguy]

I searched and searched to no avail on what type of fluid was originally in there. I didn't think of jack oil - that would have been a better choice. I did thoroughly clean the old stuff out. it had a thin consistency and smelled like brake fluid (I guess) so I went with that. Hopefully the unit is sealed enough so it will be fine for a while. Thanks for the input.

1150bob sorry for being snippy-you clearly meant curiosity without snarkyness.

[salty_monk]

Yes, it would have been hydraulic fluid - that stuff stinks when it gets old too. My father used to be a hydraulic engineer on heavy plant (JCB, caterpillar etc) when I was a teenager & I would ride with him in the school holidays

[derwood]

ATF works fine, I used it 6 or 7 years ago and every thing is still fine.
Brake fluid is for brakes,it is designed to take up water and withstand exreme heat without boiling. it eats paint and causes oil seals to swell out of shape unless spec'd for brake fluid.
With very few exceptions Brake fluid is NOT for hydraulics. other than brakes.
ATF [automatic transmission fluid(type F, dexron II or Case TCH)] is used in many hydraulic applications including transmissions.

(When I refilled the hydraulic preload assembly I submerged the piston thing in ATF to avoid getting air in)

[cableguy]

Salty, the spring you sent me swapped in fine, although I had a bugger of a time getting it mounted to my shock. My retainer is a thicker C collar, as opposed to yours which was a plate and flat clip. I found a chassis shop to help me, and they only wanted 5 bucks The shock you sent had no compression damping left, and the cables for preload and damping adjust were different than mine. Maybe I'll see if it's rebuildable, as per 1150bob's link. For the price it was totally worth it and now I know what makes the preload adjument tick. I just hope those O-rings hold up....