Lmackattack

So I dove in a little further. I removed the upper and lower plungers from the filter pedestal. The blackend plunger with wear was from the top of pedestal and was kinda stuck in there. I could push it in all the way in but about half way out it was binding. I had to use needle nose pliers to pull it out. The lower plunger is from the bottom of pedestal and came out with my finger. The 3rd pic shows both side by side. Both have the same 21A stamp on them so I assume are the same plunger but obviously one has the chrome worn off it. The plunger spring also had some caked on crap that was not metal but was hard like plastic. Not sure what it was but it was stuck in the spring. I hope to have replacement plungers/springs next week

That's what 2 people have said now that it looks like welding slag. I think it looks like block casting that may have flacked off. I definitely will be putting in a new spring and a shim washer to see if it helps pressure come up. Your right about most of these endt675/676 motors coming right up to 80psi on start up. This is lucky to see 60. I

When I bought the truck 15 years ago. It was running about 50psi at 2100rpm. It might hold that psi with clean fresh oil but not older oil with some fuel delution in it. I swapped in a new dash gauge 5 years ago and it read the same. The truck has really only had 3 oil changes since I have owned it and every time it had fresh oil it was a few psi higher. I have mobil 1 synthetic waiting to go back in now. I dropped the oil pan and pulled the presser relief today. Spring measured 3.46" . Plunger had a little wear on it but nothing I could feel with a fingernail. The picture makes it look worse than it is. Regardless I ordered a new spring and plunger. I did find a metal chunk in the pan stuck to the pick up tube. The tube did not have a screen on it like i thought it would have. It just was some grooves cut into the pipe. I forgot to grab a pic of the tube but will tomorrow. I may pull the pump to see if any metal went thry it. If anything to inspect the pump gears.

Maybe use smaller roller diameter to compensate?

That's a good suggestion. I'd suspect it's not because it reads 60 psi at cold start but it's worth looking into.

It's not horrible for a hobby truck but I'm use to seeing the 2v and 4v engines jump to 60psi right off idle. This engine oil psi is barely increasing off idle and It takes all of 2100 to reach 41 psi. I was surprised to see my copper readings so low. I was ready to roll in a new set but now I'm wondering if thats the issue

My 77 mack with 283 tipturbine has about 25psi warm idle and 42psi at warm high idle. Cold start is 60psi I feel the oil pressure is low for this engine. It's been like this for 10 years and want to try and correct it. I did an oil sample and results were normal for a hobby truck That idles more than ddriven.i thought I was going to see high copper values but they are normal. I will be replacing the plungers and springs in both the oil pump and filter pedistal. Is there a procedure to adjust the oil pump relief spring. Or is it just bolt in and go? Thank you

seen today on facebook

Possibly but im not 100% sure. they likely sold them if a customer requested mud flaps for the truck when it was finished. my dads 77' mack went thru RG smith for the fith wheel install but it had no flaps installed

The RW700 known as the superliner 1, had lots of engine options. mack inline 6 and v8 detroit cat cummins

as i understand it They were a long time finisher for mack customers. almost all the macks i drove here in Northern Chicagoland had a yellow sticker near the door vin tag with thier name and the specs of the truck after leaving their shop. they did the installs of 5th wheels, pto, dump bodies, garbage truck accessories etc.... im not sure why they went under as they did good work. i use to buy all my pto parts from them. the guys were always knowledgeable and prices were fair

tall hood R models usually refer to the later model years of the Mack Western RS700 and the RS600/valueliner. i think the change to the tall hood was around 73 when the plus 3 cab came out? the reason for the change was for larger radiator options. it also simplified the bumper and hood assembly by omitting the hinged grill used on earlier models. i think the hoods had 4" added to the sides. here is my tall hood 700

a few reasons. 1 they had inventory issues and shortages. in attempt to keep up with deliveries,Mack was sending half loaded trailers with parts from the mack plant in PA to CA and emptie trailers back to PA just to build the westerns. 2 Mack didnt have a very large market share out west and Pete / KW was fastly gaining in popularity 3 i also heard staffing issues due to the laid back CA culture but who knows

I replaced my rood skin. used a drill with spot weld removing bit think its called a roto broach?. . drilled about 100 holes around the rain gutter and pulled the roof off. then pulled the gutters while i was there and replaced them too. the new roof was glued on with panel bond with 25 clamps holding it overnight. had to drill my own holes for the air horns and lights.

look at the spring end caps. are the springs centered? or almost touching the box?. is the trunion bushings tight? or pushed out?. track rods good? look to see if bushings are rubber or upgraded to urathane. when its loaded and you turn do the axles stay put or walk sideways. look for rust and rot at the lower trunion. patch welds? look at frame rails where trunion bolts to for rot.

I recall a bulletin that said 3' minimum of metal pipe off a compressor until it could go into some other material. it was from the 1980's

the parts guy. who was also a mechanic said he always found them in camelbacks when doing a rebuild on them. i know they come in the heavier versions but i had never seen them in 34k. i might return them as i see no need for what i do with the truck.

that was my other thought as well.

on My 77' RS700L with 34k mack camelback. It did not have the steel spacers inside the aluminum caps when I pulled them off. The few other 34k I have worked on also did not have them. Everyone is telling me they should have it but I think its only used on heavier axles? whats the story with these? #11 in this photo.

I Have 1977 stud pilot 34k axles and looking to swap over to hub pilot. Does anyone know if 34k and 40k hubs can swap. I have access to a junk mack truck with 40k hub pilot hubs and hoping they will swap.

thats what i thought. with out any load on the rear driveshaft i dont think it will engage as it cant sence any speed difference between drive shafts.

i pulled my rear rear blown diff out. I found a crack in the axle housing and it needs to be welded on.. will the truck be able to be driven to a weld shop 5 miles away with just the front diff installed? just want to avoid a tow bill if i can.

i know the truck was in a fire. was there any pics of it after it burnt up. i thought we had a post on here after the fire?

https://spicerparts.com/calculators/transmission-ratio-rpm-calculator