blackbelt5 Posted February 21, 2010 Share Posted February 21, 2010 Can anyone tell me what power steering box will fit this truck. 1977 R685 I have everything but the box. My box mounts on the inside of the frame.Someone said Ross HFB70 but it looks like it mounts on the outside.Any help much appreciation. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/ Share on other sites More sharing options...
fjh Posted February 22, 2010 Share Posted February 22, 2010 Can anyone tell me what power steering box will fit this truck. 1977 R685 I have everything but the box. My box mounts on the inside of the frame.Someone said Ross HFB70 but it looks like it mounts on the outside.Any help much appreciation. Thanks[/quote]Is the truck an RS or RD RS is usually on the outside of the frame RD on the inside!Usually ross on the outside ,shepherd on the inside!There were some ross on the inside as well in older trucks! Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50081 Share on other sites More sharing options...
blackbelt5 Posted February 22, 2010 Author Share Posted February 22, 2010 fjh Not sure if it is a RS-RD RS but its mounts on the inside. Trying to fine a box that will work. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50082 Share on other sites More sharing options...
Rob Posted February 22, 2010 Share Posted February 22, 2010 fjh Not sure if it is a RS-RD RS but its mounts on the inside. Trying to fine a box that will work. ThanksI assume you are looking for an integral power steering gear. That series of truck if using a Ross gear, (now TRW/Ross) will use an HF64 series gear. R.H. Sheppard gears were used but much less common of the R models in your vintage. I've only heard of one using a Sheppard, but never seen it personally.The R685 series of truck is a standard R model with an inside frame mount steering gear. Be sure to also acquire the pitman arm for the steering gear also.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50084 Share on other sites More sharing options...
blackbelt5 Posted February 22, 2010 Author Share Posted February 22, 2010 Thanks Rob i will search for a HF64. Thanks Again Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50097 Share on other sites More sharing options...
bbigrig Posted February 25, 2010 Share Posted February 25, 2010 My old man worked at Mack in the parts dept. for 30 years.He says the HFB70 box is a late 80's heavier box. You should require a SGP49.part # 20QC4257P2 Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50220 Share on other sites More sharing options...
Rob Posted February 25, 2010 Share Posted February 25, 2010 My old man worked at Mack in the parts dept. for 30 years.He says the HFB70 box is a late 80's heavier box. You should require a SGP49.part # 20QC4257P2This is very true but the HFB70 series box will be quite a bit more costly and requires a little frame modification to mount. The existing frame will need two holes welded up and then reboring as the later gear has a different mounting pattern. The cost will be greater in the used market also. If the truck is to be worked it very well may be worth the extra cost and effort to install the larger gear as the HF64 always seemed to leak. I have three and they all leak.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50222 Share on other sites More sharing options...
bbigrig Posted February 26, 2010 Share Posted February 26, 2010 (edited) I hope I wasn't misunderstood. The old man was saying the HFB70 box is NOT the right box for that series of R model.The SGP49 is what it should call for made by ross. Mack part # 20QC4257P2Hope that helps. Edited February 26, 2010 by bbigrig Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50260 Share on other sites More sharing options...
blackbelt5 Posted March 4, 2010 Author Share Posted March 4, 2010 Thanks bbigrig That cross over to a Power Steer P/N = HF64101 That's the one i installed.Thanks for everyone's help Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50594 Share on other sites More sharing options...
ducky698 Posted March 7, 2010 Share Posted March 7, 2010 Thanks bbigrig That cross over to a Power Steer P/N = HF64101 That's the one i installed.Thanks for everyone's helphi, this is hfb 70 on an ozy mack.regards Grant Quote Link to comment https://www.bigmacktrucks.com/topic/12737-1977-r685/#findComment-50818 Share on other sites More sharing options...
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