The design consists of the features of shape, configuration and ornamentation for a spring housing for a suspension shown in the drawings. The sectional lines and sectional line reference numbers shown in the Figures 1, 2, 3, 4, 21, 22, 23, and 24 are for illustrative purposes only and form no part of the claimed design.FIG. 1 is a front elevational view of a first variant of the spring housing for a suspension;FIG. 2 is a rear elevational view of the spring housing for a suspension shown in FIG. 1;Fig. 3 is a right side elevational view of the spring housing for a suspension shown in FIG. 1;FIG. 4 is a left side elevational view of the spring housing for a suspension shown in FIG. 1;FIG. 5 is a top view of the spring housing for a suspension shown in FIG. 1;FIG. 6 is a bottom view of the spring housing for a suspension shown in FIG. 1;FIG. 7 is a front, top and left side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 8 is a front, top and right side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 9 is a front, bottom and left side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 10 is a front, bottom and right side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 11 is a front and top perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 12 is a rear, top and left side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 13 is a rear, top and right side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 14 is a rear, bottom and left side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 15 is a rear, bottom and right side perspective view of the spring housing for a suspension shown in FIG. 1;FIG. 16 is a sectional view of the spring housing for a suspension shown in FIG. 1, taken along 16-16 in FIG. 1;FIG. 17 is a sectional view of the spring housing for a suspension shown in FIG. 1, taken along 17-17 in FIG. 2;FIG. 18 is a sectional view of the spring housing for a suspension shown in FIG. 1, taken along 18-18 in FIG. 2;FIG. 19 is a sectional view of the spring housing for a suspension shown in FIG. 1, taken along 19-19 in FIG. 3;FIG. 20 is a sectional view of the spring housing for a suspension shown in FIG. 1, taken along 20-20 in FIG. 4;FIG. 21 is a front elevational view of a second variant of the spring housing for a suspension;FIG. 22 is a rear elevational view of the spring housing for a suspension shown in FIG. 21;Fig. 23 is a right side elevational view of the spring housing for a suspension shown in FIG. 21;FIG. 24 is a left side elevational view of the spring housing for a suspension shown in FIG. 21;FIG. 25 is a top view of the spring housing for a suspension shown in FIG. 21;FIG. 26 is a bottom view of the spring housing for a suspension shown in FIG. 21;FIG. 27 is a front, top and left side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 28 is a front, top and right side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 29 is a front, bottom and left side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 30 is a front, bottom and right side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 31 is a front and top perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 32 is a rear, top and left side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 33 is a rear, top and right side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 34 is a rear, bottom and left side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 35 is a rear, bottom and right side perspective view of the spring housing for a suspension shown in FIG. 21;FIG. 36 is a sectional view of the spring housing for a suspension shown in FIG. 21, taken along 36-36 in FIG. 21;FIG. 37 is a sectional view of the spring housing for a suspension shown in FIG. 21, taken along 37-37 in FIG. 22;FIG. 38 is a sectional view of the spring housing for a suspension shown in FIG. 21, taken along 38-38 in FIG. 22;FIG. 39 is a sectional view of the spring housing for a suspension shown in FIG. 21, taken along 39-39 in FIG. 23; andFIG. 40 is a sectional view of the spring housing for a suspension shown in FIG. 21, taken along 40-40 in FIG. 24.