MCfan Posted October 2, 2012 Share Posted October 2, 2012 Back on 9/18, Dan (Dans '70 Z20) posted a link to a NOS set of Rear Bumper Guards offered on eBay. I had been looking for a nice set of rear guards to complement the front guards that came with my '70 SS car so I snapped them up. Thanks again for that link, Dan! They arrived on Thursday last week and were in perfect, new condition. I went ahead and installed them that afternoon so they would be in place for Saturday's local car show. While it is a very straight forward project to install bumper guards, there are no predrilled holes or markings on the rear bumper to guide you. Using the instructions and template provided, I was able to get them positioned and installed correctly. I also created a brief photo journal of the installation process in case anyone is planning to mount a set of rear guards (especially a used set that doesn't have an instruction sheet or template to guide you). Here's a direct link to the photo journal if anyone is interested: Installing Rear Bumper Guards Here's an "after" picture. I really love the look of bumper guards on first gen Montes! Link to comment Share on other sites More sharing options...
70mcarlo Posted October 2, 2012 Share Posted October 2, 2012 Thanks Dennis! I noticed your new guards in the photos you posted earlier with the fall colors. I also picked up a set of perfect NOS rear guards awhile back - your info will certainly help when installing them (not there yet). Thanks again for sharing your experience!!! Link to comment Share on other sites More sharing options...
Murphy Posted October 2, 2012 Share Posted October 2, 2012 Hey Dennis, nice instructions! By the way, there's a little smudge on the bumper, leftside..... Link to comment Share on other sites More sharing options...
MCfan Posted October 3, 2012 Author Share Posted October 3, 2012 How many times did you measure and re-measure before you actually placed the drill big on the bumper? After it was drilled and before you installed the guards did you coat the inside of the hole with any primer or other form of rust preventive prior to mounting the guards? Rob Rob, Short answers: At least three times each and Break Free CLP for rust prevention Long answers: The top hole controls the horizontal spacing and the bottom hole controls the vertical orientation so I measured and remeasured each one three or more times. The position of the upper hole was dictated by both the ruler and the template. Even after carefully taping the ruler to the bumper (on each side, respectively) with the 9 1/4" mark lined up with the center mark on the bumper and the template held against the end of the ruler, I still checked the mark (made with a black Sharpie pen) for the top hole at least three times before striking the center punch. The two bolts in each guard are not parallel but are perpendicular to the bumper surface at each individual hole location so you have to be careful that the center of the hole is projected from the template and marked perpendicular to that surface. I remember checking that several times both before and after I struck the center punch. Once I was satisfied with the center punch location, I enlarged it to a pilot dimple with a 1/8" bit and moved on to mark the lower hole. The position of the lower hole was dictated by both the template and the level to insure it was on a vertical line with the upper hole position. Since the lower hole is further away (inboard) from the ruler, it is very easy to get some sideways cant on the template while transferring the hole center location from the template. The level helps, of course, but I still had to check and adjust the center mark with the level against the slope of the bumper after the template had been removed. On the right hand side, I actually made three different center punch marks (all within the diameter of the final 11/32" hole) before I made the pilot dimple for the lower hole. After both hole locations had pilot dimples, I again checked their vertical alignment with the level before drilling the holes with the larger bit. The instructions called for a 3/8" hole (typical auto tolerance for a 5/16" bolt) but I wanted to use the smaller 11/32" bit and not have to enlarge the holes, if possible. Everything bolted up fine but a 3/8" hole will obviously give a bit more margin for error or adjustment. I am a great believer in Break Free CLP as both a lubricant and a rust preventer so that is what I used on the bolts, lock washers and the holes (but forgot to mention in the photo journal). Coating the edge of the hole with primer is probably a more durable rust prevention measure. During a previous project last summer, I had painted the back side of that bumper with Dupli-Color's Bumper Chrome so hopefully everything is still protected. Link to comment Share on other sites More sharing options...
wandalee Posted December 20, 2012 Share Posted December 20, 2012 DID YOU HAVE TO REMOVE THE BUMPER TO ATTACH THE GUARDS.... I DONT THINK I CAN GET MY HAND BEHIND THE BUMPER TO ATTACH THE NUTS TO THE BOLTS...... THANKS...... WANDA Link to comment Share on other sites More sharing options...
MCfan Posted December 20, 2012 Author Share Posted December 20, 2012 No need to remove the rear bumper, Wanda. As I remember, it was a bit tight for my fat hands but I used a rather flat GearWrench (racheting boxend) while laying on my back under the rear bumper and got it done without any first aid. Those are 5/16" bolts so it would have been a 1/2" hex head. Bolt hole spacing and vertical alignment are both critical. If you don't already have a template that fits the contour of the rear bumper and accurately marks the hole locations, I would encourage you to make one - it's simple to do - just trace and cut. Also, using a level to be sure the holes are vertically aligned is very important. I'm getting ready to install both front and rear guards on my other '70 so I made the template shown below - rear bumper on one edge and front bumper on the other. Good luck with your project. I think bumper guards make just about any first gen Monte look better. I'm still on the lookout for a nicer set myself. Link to comment Share on other sites More sharing options...
Canuck Posted December 20, 2012 Share Posted December 20, 2012 I managed to remove and reinstall my bumper guards on both Montes without must issue. No need to remove the bumper. It took some time and a flat ratchet wrench was helpful. Link to comment Share on other sites More sharing options...
LostnFound Posted December 20, 2012 Share Posted December 20, 2012 Show off! Probably didn't even scratch anything. LOL Link to comment Share on other sites More sharing options...
wandalee Posted December 20, 2012 Share Posted December 20, 2012 REPLACING BOTH REAR AND FRONT BUMPERS THEY HAVE THE GUARDS, I WILL MAKE TEMPLATES OFF THE OLD ONES.... PLAN ON HAVING OLD GUARDS RE- CHROMED...... THANKS FOR THE TIPS..... WANDA Link to comment Share on other sites More sharing options...
overdrive Posted December 21, 2012 Share Posted December 21, 2012 Wanda, if you're replacing the bumpers, they're available with or without the guard holes already there. The cost of the bumpers are the same. Buy them with the holes and the hole edges will be chrome plated and they won't rust easily. --------------------- When I installed a used pair on a rear bumper that didn't have the holes, this is what I did: Put masking tape over the bolt holes on the guards and let it extend out onto the sides. Using a fine point marker, mark the center line of the hole on the tape on each side of the guard. Put tape over the mounting area on the bumper and hold the guard in place. Starting with the top hole, transfer the marks on the guard to the bumper to lay out the horizontal center line. Next, while holding the guard in place, make vertical marks along the edges of the guard where it meets the bumper, to lay out the vertical center line. Then, make a vertical mark on the horizontal line, halfway between the outer vertical marks, to locate the center of the bolt hole. Center punch, drill a small pilot hole and then the final hole size. Bolt the guard on just tight enough so that you can still move the bottom of the guard side to side and adjust it vertically. Now you can lay out the bottom hole. All of the front bumpers have the lower guard mounting hole already there. Dan Link to comment Share on other sites More sharing options...
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